HQs in complex attacks

[ghibli]

Hi all,
I'm carrying some experiments issuing attack orders to high level HQs (e.g. division size or more) to see how the AI handles subordinate HQs. I get all HQs from the top to the lowest level concentrating around the FUP, then lining up at uniform distance from the place where I ordered the attack. The assault only involves line troops (meaning HQs and support troops, like AT guns and flak all left behind). The HQs only rejoin the assaulting troops at the end, (often following the most strange routes). In this way a Battalion HQ can be separated several km from its companies (see figure, attacking with armoured division). This is probably well known but:

• How far is this realistic? Wouldn't it be better if HQs (and short range supporting units) followed their own line units from a certain distance, according to their level in the OOB, and/or according to some parameter in the attack order (e.g. aggro)?

I often need the firepower from HQs in assaults, especially armoured ones, which have a core of tank units, and generally, rather than attack, I found that the best solution is to issue move order with attacks flag turned on.

I find the game to be extremely realistic at low scale (regiment to division map boss), which allows me to exert manual control on most of the support troops; also the handling of front line troops is just fine. However the interplay of line and supporting units is often difficult to obtain if left to the AI.

Cheers

 

[jimcarravallah]

Hi all,
I'm carrying some experiments issuing attack orders to high level HQs (e.g. division size or more) to see how the AI handles subordinate HQs. I get all HQs from the top to the lowest level concentrating around the FUP, then lining up at uniform distance from the place where I ordered the attack. The assault only involves line troops (meaning HQs and support troops, like AT guns and flak all left behind). The HQs only rejoin the assaulting troops at the end, (often following the most strange routes). In this way a Battalion HQ can be separated several km from its companies (see figure, attacking with armoured division). This is probably well known but:

• How far is this realistic? Wouldn't it be better if HQs (and short range supporting units) followed their own line units from a certain distance, according to their level in the OOB, and/or according to some parameter in the attack order (e.g. aggro)?

I often need the firepower from HQs in assaults, especially armoured ones, which have a core of tank units, and generally, rather than attack, I found that the best solution is to issue move order with attacks flag turned on.

I find the game to be extremely realistic at low scale (regiment to division map boss), which allows me to exert manual control on most of the support troops; also the handling of front line troops is just fine. However the interplay of line and supporting units is often difficult to obtain if left to the AI.

Cheers

In the US Army, line unit HQs at BN and above had a heavy contingent of non-combat troops assigned as organic assets,including contingents for supply, medical care, and administration. Organic combat assets are either designed for long range support roles or self defense in rear areas rather than direct fire attack. While the game may not reflect these units in the Estabs, it would be logical to keep those level headquarters out of heavy combat situations until subordinate maneuver / combat units have established a more or less permanent defense position for the HQ assets to occupy.

 

[GoodGuy]

Hi all,
In this way a Battalion HQ can be separated several km from its companies (see figure, attacking with armoured division). This is probably well known but:

• How far is this realistic? Wouldn't it be better if HQs (and short range supporting units) followed their own line units from a certain distance, according to their level in the OOB, and/or according to some parameter in the attack order (e.g. aggro)?

I often need the firepower from HQs in assaults, especially armoured ones, which have a core of tank units, and generally, rather than attack, I found that the best solution is to issue move order with attacks flag turned on.

Historical example, in a defensive posture, based on the deployment of the German 45th Infantry Division, which ended up having to defend a front sector of 30 kilometers, in July 1942:
The sector was in Russia's south, in the so-called "Black Earth Region". That region featured open prairie and huge fields, sprinkled with woods, canyons (created by erosion), small rivers, single roads and railroad lines, as well as numerous villages, hamlets and former state properties (eg. collective farms, kolkhoz buildings, etc.).
In early July, the 45th ID had started to dig static defenses (zigzag-trenches, B-posts, etc.) in this diversified landscape, as major hostilities had died down, and since the region suited well for static warfare. The unit worked hard to flesh out these defensive lines, but also forced local civilians to build trench networks and cut-and-cover shelters. Since the unit had to cover a 30-km strip, the Division commander had no other choice than to put all of its 15,000 troops on the HKL (Hauptkampflinie = main battle line, MBL) (the actual strength of the division on July 7, 1942: 15,224 troops, at the end of July: 8,083 troops). The 2nd Army HQ staff report stated laconically: "Neither the Army, nor the Corps and Divisions have reserves at their disposal."

While in 1941 German MBLs used to rather consist of a collection of foxholes, outposts, wooden bunkers, MG nests and rare trenches, the Germans had not switched to building more sophisticated defensive networks until 1942, when they appeared to be forced to go on the defensive.
During the course of the first 6 months of 1942, the Germans would eventually build continious defensive lines, put up barbed-wire obstacles, create tank ditches, lay out AT and AP mine belts, somewhat resembling the trench lines of the First World War, to some extent.

At that point of the war, during an attack, quite some Russian commanders would still recklessly send wave after wave (from Coy-sized formations to even Bns) to storm the German MBL, where then, according to various German veteran accounts, the relief detail of say a trench line with an MG position, would quite often find only the MG gunner alive on the next morning, and all the friendly riflemen in the trenches killed, but also a myriad of Russian bodies in front of the MG, so that they couldn't even see the ground anymore.

In the 45th ID sector, the Russians were sometimes as close as 300 or 400 meters, where say clearly visible heaps of earth at the edges of some woods indicated newly built Russian foxholes.

The MBL's main task was to slow down or halt the enemy attack's momentum, by screening the no man's land right in front of the MBL. Behind the MBL, the Second Line was arranged in a way that favored the tactical use of the terrain, buildings, elevations or choke points, so that a breakthrough in the MBL could be dealt with.

The Second Line (SL) was usually 2 km behind the MBL. If the layout of the terrain allowed for proper visuals, the FOs (forward observers) would then also put up their B-posts (or even just use foxholes or buildings) in the Second Line.
The mortar Coys and the leIG 18s were also put on the Second Line (SL) or between MBL and SL, if the leIG 18s were not needed for direct fire at the MBL, or if it was too dangerous to employ them that close.
At the SL, you could also find a first set of HQs, namely the BN (field) command posts, often just primitive earth bunkers with just a telephone, sometimes even a telephone switchboard allowing for simultanous calls to and from different Coys, radio(s) and several messengers. This short distance to the MBL allowed the Bn commander to follow and observe the action at the MBL, but also to lead and directly influence the events unfolding at the MBL. On this account, Bn commanders often became the main responsible of the unfolding combat, so - in some ways - like a leader of a Kampfgruppe on small scale.

Behind the Second Line the Germans then put the Panzerauffanglinie (translates to tank cushion line, or tank blocking line, where the AT guns were placed, but also - quite often - AA guns, which were on AA duty, of course, but were also supposed to open up on enemy troops (filtering through the MBL), usually set up in (camouflaged or hidden) ambush positions.

4 to 5 kilometes from the MBL, and behind the tank blocking line, the Rear Area Line was established. This line was used as FUP for the divisional artillery. With its range of 10 to roughly 16.x kilometers, it could control/cover a large area in front of the MBL, and fight the enemy - using a detailed pre-planned fire matrix - even before he could reach the first German line positions.

Behind the Rear Area Line (RAL) was the Divisional Rear Area Zone (RAZ), where the Regimental command posts, the main casualty station, the central offices of the Signal Bn and the baggage trains/columns of the line units resided.

The Division HQ used to be set up several kilometers behind the RAZ. Usually set up in woods, canyons, etc., either using tents, a so-called "Befehlsbus" (= command bus) or more sophisticated bunkers, the Division Co, the Ia, the Ic would then be able to command and control events from a relatively short distance, where dispatched messengers could even relay orders in a timely manner, in case communications should fail.

The adjutancy was usually set up even further away, usually 15 - 20 kilometers behind the MBL, accompanied by the quartermaster, usually using buildings and solid structures as offices. At that distance to the front line, their offices were usually outside the Russian artillery range. After the numerous breakthroughs on the line 40km from Moscow, during Winter 1941, where divisional posts, small depots and adjutancies got steamrolled, this distance was now deemed to be halfway safe by the Germans.
In a brigade, a division, army corps or army, the adjutant administered reinforcemements, managed the personnel office, the awards and recommendations and officer staffing. The position might correspond to the G1 (A1) officer in modern NATO staff HQs.

After the German experience with the Russian steamrolls in Winter 1941/42, the Germans tried to give their combat zones more depth.
The 45th ID virtually occupied each of the 18 villages that resided in its combat zone and expanded each of them to outposts, and even the small river Foshnja in its rear was dammed by engineers and blocked with mines. In the far rear of the Division the Germans had erected blocking positions (so-called "Riegelstellungen"), which were not manned, but which could be used as "Alamo"- positions, in case the other lines (MBL, SL, RAL) would get crushed.

Due to the fact that manpower was a general if not universal problem for the Germans throughout the war, these attempts - to create more depth - were hampered when the Germans lost the initiative and when Russian defense stiffened. This often resulted in situations where lone divisions had to switch to a rather static defense and where they then had to cover large front sectors which often restricted the overall-depth to around 15-20 kilometers. And even though the majority of the troops was then put on the MBL, the MBL then often rather resembled a (long) thin line of troops than a properly manned MBL.
In 1914 the depth of German lines (and probably Allied lines too) amounted to around 10 kilometers, while in 1918 - corresponding to the progress of weapon technology - the depth had doubled.

An officer in the Ia office of the Panzer AOK 2 (2nd Tank Army) put a transscript of a phone call in the HQ's book of (phone call) records, on June 5, 1942:
The record stated that the German defensive line was "vorne sehr dünn" (= very thin at the very front).
In April 1942 a general wrote that "jokers already suggested to equip large parts of our so-called 'position' with Russian signs saying 'Passage forbidden' (or 'no trespassing') ", as all the lines in his sector had defensive structures, but some parts only an extremely thin line of troops, so actually almost no troops.

Within 3 months, the sector the 45th ID had to cover had expanded from 23 km to 30 km (in early July), as neighboring units had been pulled out of the line, because they were needed elsewhere.
EDIT: If I am not mistaken, the 45. Inf Div was deployed to this sector in late June or early July, as it was deployed in a sector of Army Group B (the rather central group in Russia, at that point) before. This means that other units had started to build these defenses during those 3 months, and the 45th then fleshed out the defensive lines.

I am not sure if the player can actually simulate this by using the custom formation feature (eg. stretching a given Coy on a wide front with 600 meters width and the smallest available depth, and setting the facing to "manual"), as the unit's (white) footprint does not seem to change, actually.

Part Two: Next post

 

[GoodGuy]

Part Two

Back to your plan to use HQ armor assets: Most of these vehicles were Befehlswagen (command vehicles), and were equipped with extra radios (means additional medium or long range radios needed for C+C) and often even featured a 2nd radio operator, depending on echelon level. Such a command vehicle could be a tank, a halftrack, a scout vehicle (armored car, a command truck with long range radio or even a bus (Befehlsbus).

On tanks, the main guns were then often removed, to make room for the extra equipment, and the loader position was canceled, to make room for an additional radio operator, only the MGs remained in the vehicles. If there still wasn't enough room, one of the MG was removed, as well. These tanks then received dummy guns, meant to scare the enemy.
Some Command tanks actually kept their main guns (it's not clear whether field repair shops "upgraded" them or if the factory put it out like that), but then they usually carried a reduced amount of ammunition, to create room for some of the extra equipment, at least.
If a HQ had additional vehicles (eg. tanks), often just 2-3 tanks, besides the mentioned command vehicle, the vehicles were then used to protect or escort the unit commander in contested areas, or to protect the perimeter during an enemy steamroll.
Some commanders (maybe like Rommel) seemed to prefer halftracks or armored scout cars (6- or 8 wheels) which allowed for better observation of the terrain and planning of the tactical setup of line units.
Occasionally, these "HQ tanks" were sent to combat as emergency replacements or to cover tank retrievers during their missions.
But of course, these tanks did not bring the HQ's "deskpersons" with them, so placing the entire HQ body on the frontline would not make sense, as you'd most likely lose all or parts of its infrastructure (supply column -> trucks, transportation, weapons, HQ personnel) in the process, just to get a few tank shots in. Divisions usually had a security element, which secured the HQ perimeter, the small divisional supply base, or other divisional bodies. Some of them were MPs, but some of them were fully trained and experienced soldiers, so some parts of such element could be employed in an infantry role, of course.

Only a function to merge or rearrange unit compositions on-the-fly would be able to accomplish what you have in mind, though.

Actually, such a function could also cater for the fact that - historically - reinforcements were even brought in during the course of an operation. At least the Russians and the Germans exercised this.
The Germans Army, for instance, besides reinforcing depleted units with recruits (which had finished training) drawn from the "Reserve Army" in Germany (responsible for training new recruits and also using the skeleton, means officers and NCOs of depleted or almost destroyed units to erect new units or to rebuild the particular units) in rear areas or in the homeland, they also filled up depleted or battered units with troops drawn from other units, sometimes even right behind the front at the FUP or even at the MBL, where the "milked" units then often ceased to exist (unless they were rebuilt later on) or were sent back to Germany as skeleton units.

In Russia, at the southern front (in 1943 IIRC), large troop contingents (reinforcements) were also drawn from Luftwaffen-Felddivisionen ("Air Force Field-Divisions", which were - starting in October 1942 - raised from around 250,000 air force ground, service and excess troops, with little or no ground combat training) and incorporated into depleted Army units, temporarily, until Wehrmacht personnel could fill (some of) the ranks. Since these air force divisions had little to no ground combat training, and since they were seen (at best) as third-rate units by wehrmacht officers, they were usually tasked with occupation duties in other theaters. Still, 14 of these divisions were deployed at the Eastern Front, where the partial lack of modern material (the 15th Luftwaffen-Felddivision had to use french 19th century 150-mm guns, with barrels made of bronze) and the lack of training and experience then led to unsual high losses, which amounted to up to 80% (ie. : the Luftwaffen-Jäger-Regiments).
Since the General Staff of the Army had demanded to incorporate this large force pool into the Heer (Army), numerous times, it seems like Hitler gave in eventually and ordered to hand over all of these troops to the Army, in September 1943. The Army replaced almost all of these units' officers with experienced Wehrmacht officers. Officially, the air force field-divisions had ceased to exist at that point, but the units could still be identified as their new designations carried an "L" ( for Luftwaffe) in their names: Felddivision (L) .

Wehrmacht units also regularly exercised such on-the-fly reassembling with their own units, say 3 line Coys would have lost 2/3 of their troops, they then combined all three Coys to gain one full strength Coy, or - quite common as well, they would use the 3rd Coy to fill up the 1st and 2nd Coy, to gain two 50% strength Coys. The re-assigned troops then stayed with the new Coy until the end of the operation, or until the unit was pulled out and rebuilt or filled up otherwise, but it was also possible that re-assigned troops would stay in their new Coy. In general, the Germans seemed to try to keep NCOs with good/efficient "teamplay" in the same unit.
It was also not umcommon, that the milked Coy ceased to exist as it was never replaced, or that the Bn had to wait (a long time) for a replacement Coy until a major reorganization took place. Also, many Bns had to hand over one or 2 Coys to other units, where such "borrowed" units kept their designations and were sent back to their original unit after situations could be rectified, but there were also many instances where such companies were permanently assigned to other (often stronger, or more experienced, or more effective) units, taking over new designations, badges and numbering. Some soldiers had a long list of subunits in their deployment records.

Unfortunately, the current engine does not allow for such fluid but also historical and realistic troop management.

 

[GoodGuy]

Unfortunately, the current engine does not allow for such fluid but also historical and realistic troop management.

The main way of reinforcing exisiting units was - of course - to draw new recruits from the pool of the Reserve Army.

Basically, every Division in the field had particular replacement units (in the field) that would be responsible for keeping up the reinforcement cycle.
In order to create smooth procedures, "Feldersatz"-Bns (= field reinforcement Bns) - as fixed/organic part of the Division - were created. In these Bns, replacement recruits from the Ersatz-Bns (the unit that provided boot camp training) in Germany were collected in the rear area of the Division and given so-called final "close-to-the-front"-training. This way the Division had its own reserve pool to compensate immediate losses. These replenishment contingents were listed as organic parts of the Divisions, so they were listed in the OOBs accordingly, but they did not necessarily contain (full) troop contingents (eg. their troops were used to reinforce the line units, and new recruits had not reached the Bn yet). Such Bn was could also be employed like a regular unit - as "fire brigade", or for immediate rear area anti-partisan duties.

5 Feldersatz-Bns received name designations, the other Bns were numbered from 1 through 671, a batch of 7 Bns received numbers between 702 and 719, and a batch of 24 Bns received numbers between 1048 and 1712.

Usually, a particular military district in Germany was responsible for reinforcing a particular unit or a set of units (I am not sure whether the Germans were able to keep up that recruitment regime at later stages of the war, and I am not sure whether several different military districts could also reinforce the very same unit, or not).

Following an order from the OKH in January 1942, the Feldersatz-Bns were supposed to be established in the homeland (from the troops of the Ersatz-Bns), to be transported by train to the end point of the railroad line and then supposed to walk the (short) last distance to the Division zone. While for a Division on R+R in Germany or locations near railroad hubs in other countries this just involved a short walk, it could involve a half day of marching to units in the field, say in Russia. Still, and quite obvious, the Germans tried to make sure that replacement contingents reached the Divisional zone in a timely manner and halfway fresh (and not totally exhausted by several days of marching). This part of the reinforcment regime diminished with deterioriating fortunes of war.

Another part of the OKH order was that 8 Feldersatz-Bns were designated to be transfered by truck exclusively. Some sources deliver some confusing info here, as these 8 Bns did not seem to belong to particular Divisions, but were in fact temporary Bns (like the "march Bns") of recruits, that were given priority (hence the trucks) over regular march Bns (see below).

The second method of transfering reinforcements was the forming of "march Bns", where these Bns were supposed to be relocated by train until they had reached the border of the Reich (or protectorate, eg. Poland, Czech) and where they then had to perform a land march (on foot?) for the remaining distances to their destination units.
These "Marschbataillone" (= march battalions), which avgd. 800 - 1,000 troops in size, were organized in 3 to 5 Coys plus a small Command Coy, as well as a properly sized field kitchen. These troops in those pretty large Coys only had hand guns (which - by the German definition - could mean carbines, MPs, pistols and even StG 44 assault rifles), but no heavy weapons. In order to enable these troops to defend themselves against attacks or resistance raids/ambushes, they were usually given a few MGs (most likely LMGs). The troops were supposed to get additional gear and heavy weapons at their destination units. While such march Bns were commonly used in the Western theater (especially 1944/1945), in Italy and on the Balkans, I am not sure whether the Germans really regularly sent out march Bns to say units in the Russian steppe. There are veteran accounts stating that troops in Infantry units literally had to walk for days to get to FUPs or defensive lines in the South of Russia, due to lack of transportation, and also reports about fighting withdrawals (on foot) for weeks, during the Russian onslaughts (with initial pushes of 80 km and then 400 - 600 km in Russia's South) in late 1943 (IIRC), and these weren't stragglers, but parts of relatively large elements, but I doubt that land marches of several weeks were expected of green recruits.
Whatsoever, it seems like such march Bns were increasingly used in early 1944, so that the Heer (army) felt inclined to add an entry in the KStN required-strength sheets, which defined the organization of the Bn staff, but also showed exact allocation figures (shown in %) defining the composition of the Bn (detailing how many replacement troops of the different branches - ie. Inf, Artillery, Cav/recon - would have to be included), to avoid chaotic/random pulling of troops that are not needed in the destination units. Just like those mentioned 8 Bns, the march Bns were only temporary formations meant as pool for replenishement of units at the target destination, or for establishing new units. Officially, these units were not supposed to be sent into combat.

The divisional Feldersatz-Bn usually carried the designation of the destination unit. While -technically- the units were just temporary pool and final field training units meant to manage the transfer and eventual distribution of their troops to the Division's units, they were also used as divisional reserve as a whole occasionally, means they were fully committed as if they would be organic Bns of the division, during a number of operations and defensive battles.
The actual training of raw recruits was performed by the Ersatz-Battaillone (replacement Bns, note: no "Field" designation in there), with their home bases or camps/forts in (almost) every military district, as mentioned above.
Replacements for the officer staff often came from other Ersatz Bns, one reason might have been that the number of officer schools was way lower than the number of barracks/military districts feeding the Bns with grunts and NCOs.
Technically., the Ersatz-Bns were subordinated to the Ersatz-Divisions, and usually earmarked to train new recruits for particular units in the field, but they also handed over Coys or even the entire Bn to totally different divisions, as well, when trained recruits were needed elsewhere.
In turn, the Ersatz-Divisions were often just skeletons (officer staff and administration), but could also hold say Bn-sized troop contingents. Since these Ersatz divisions and Bns were also part of the Home Army, some contingents were actually held back and stationed as armed reserve, in case civilians, POWs or concentration camp inmates would start a revolt. Hitlers fears of such uprisings were exploited by (mis-)using cooresponding ("Valkyie"-)Plan on the 20th of July, during the attempt to assassinate him. The plan demanded Ersatz-units to occupy vital points in Berlin and other important cities, such as crossroads, radio stations, political offices and military command and cmmunication centers, in time of domestic crisis.

Example for the use and deployment of Field-replacement Bns:

The Feldersatz-Bn 45, created in August 1939 to replenish the 45. Infantry Division, was handed over (as a whole) in 1940 to the 429. Inf Regiment to become that Reg's 1st Bn, as that Regiment had handed over its original 1st Bn to the 168. Inf Division.
After the Feldersatz-Bn 45 was reformed (using new recruits) in April 1941, it was then dissolved in March 1942.
This corresponds with the actual strength report of the 45. Inf Division from July (full strength in early July, see preceding posts), so the 45th Division must have used the troops to replenish all of its line units to regain full strength (I even think it had around 200 troops more than the official required target strength). It's also possible that parts of its troops were used to replenish other units, though.
Whatsoever, it then took a long time until the replenishment-Bn was re-created again: It was formed in July 1943 again, but it then lost all of its troops, except for its staff, in October 1943, which obviously means that its troops and NCOs were used to replenish the Division's units. The same month, the Bn - still containing the staff only - was renamed to Feldersatz-Bn 98, and was fully replenished with troops from a Ersatz-Bn in February 1944. It seems that, despite the name change, the Bn kept to be attached to the 45. ID, and the 45th still listed it as Feldersatz-Bn 45 in June 1944, and the 98th Inf Division's Feldersatz-Bn carried the number 198. Both the 45th ID and the Feldersatz-Bn 45 were destroyed in the Bobruisk pocket the same month.

The 45. Inf Div was re-established in July 1944, but now designated 45. Grenadier-Division, then renamed to 45. Volksgrenadier-Division in October. The Feldersatz-Bn 45 was recreated in Novermber, either with the number 45 or 98, and then attached to the 45. VGD. The 45th VGD was then shattered (along with its Feldersatz-Bn) in January 1945 at the Weichsel river. With another reforming of the 45th VGD not having finished, remnants of its Kampfgruppe went into Russian captivity towards the end of the war.

This demontrates that these Bns were actually not just used as replenishment pools, and that they were not recruits pressed into service as march Bns in France or Holland, like some dubious online sources keep to claim, and it also demonstrates that they were also committed as reserve units (with varying weapon loadouts and varying success), as many of them were still almost fully trained troops that just lacked combat experience.

 

[GoodGuy]

MARCH BNS IN AFRICA

A major exception was the Tunisia campaign in North Africa (1942-1943): In order to counter the beginning operation Torch, the Germans tried to gain French Tunisia as retreat area for the battered Panzerarmee Afrika (Tank Army Africa) and other German and Italian units. For this goal they needed troops from European sectors that could be spared and sent to North Africa. Kesselring, the Supreme Commander South, scraped the "Africa march Bns" (Afrika Marschbattailone) together, which were residing at locations in Southern France, Italy and the Balkans, and actually rather awaiting additional training in those rather hot regions as preparation for desert warfare and awaiting delivery of proper equipment, and sent them to North Africa right away, even though their equipment was inadequate and even though these troops lacked training. Some of the Bns were renamed to "Tunis Feldbataillon".
According to Douglas E. Nash ("Rommel's Lost Battalions", 2012), these Bns fought alongside regular German units covering the retreat to Tunisia, but were then, according to the original plan for these march Bns, incorporated as/into regular units or dissolved and their troops distributed to the regular units.


HINDRANCE TO RAILWAY TROOP TRANSPORT AND SUPPLY

Another factor hampering the relocation of field units (not recruits) to reinforce defensive lines, was the fact that the SS had managed to get the right of way for their trains deporting Jews, Sinti, Roma, political opponents, homosexuals, Russian POWs and foreign slave laborers to the concentration camps. More than often, trains packed with desparately needed reinforcements or supplies for the front line or wounded soldiers heading back to Germany, had to wait on railway sidings. This added - according to several German historians -, and in addition to the ever increasing number of aerial hub bombardments and bombardment or strafing of reinforcement and supply lines, such severe pressure on at least one Army in 1944 and also in late 1943, that this is attritubed to have contributed to its respective untenable situations. Even though the Germans were very successful at repairing tracks within hours only (the trains would usually commence their trips at night), these additional holdups created critical delays on unit relocation and supply.
German historians and researchers could not establish an answer to the question whether the Supreme HQ knew about the situation at all, whether it (silently?) agreed to the SS's "right of way", or whether Hitler himself, who kept complaining about the deterioriating transportation situation, knew about it, and whether the SS just claimed this "right" on own initiative, or not. These findings emerged during the last 5 - 8 years, when German historians researched the level of involvement of the Reichsbahn (state railway) in the holocaust, and the question whether engine drivers and Reichsbahn employees could have known about the holocaust (since they claimed they didn't get to know anything), whether they could be held (criminally) liable for assisting in the killing (transporting them to camps or gas chambers), and whether large parts of Germany's population could have heard about the proceedings in the camps by word of mouth from the railroaders, or not.

 

[GoodGuy]

The Pionier-Bn 81 (also "Pi.Bn 81", engineer Bn that was attached to the 45. Inf Div.), used to draw reinforcements from the Ersatz-Bn 86 in Germany. Since the more specialized branches (engineers, Cav/Recon, Artillery) needed additional/special training, they could not draw recruits from the Feldersatz-Bns.

For all branches, basic additional training (driving lessons, MG qualification, basic sniper training) could be provided in Germany during or after boot camp (according to the planned future assignment), but could also be partially provided in the field.

Special qualifications (artillery gunner, medium/hvy mortar operator, AT gunner, etc.) were usually also taught in Germany, parallely during 4-6 weeks of boot camp, or right after boot camp, but then trained in the specialized Ersatz-Bns (eg. Artillery-Bns [AT, artillery guns, mortars, rocket launchers], tank training Bns, engineer-Bns, para Bns, mountain Bns, etc. etc.).
Engineer Bns could still be deployed like regular Inf Bns, but especially the non-motorized Bns (like the 81th, I think only the 3rd Coy was motorized, the other Coys were horse-drawn ones) lacked heavy equipment, unlike the line Inf Coys.
For instance, the Pi-Bn 81 had only 6 HMGs at its disposal. When ordered to defend a certain objective in October 1942, the Infantry Regiments had to send mortar elements (4 medium or hvy mortar pieces and crews) to bolster the Bns defensive power.

Engineers were also used as scout elements and forward details, even though that habit was critized by Wehrmacht officers and was mostly seen as bad practice, as the minimum setup on such occasions would have been a set of armored scout cars. Elements of the 81th were still sent forward to scout and gather intel about bridges that were destroyed by Russian partisans when the Red Army retreated in 1941 and 1942, on a regular basis, usually the 3rd mot. Coy, which was assigned to the "Vorausabteilung von Stolzmann", an Oberstleutnant sent by the Corps to create and command the ad-hoc forward element. Such intel then helped to plan the future route of advance and to establish which bridges could be repaired and where to build pontoon bridges. The 81. Pionier-Bn was also ordered to attack villages and airports occupied by the Russians, and many of these small scale engagements were carried out by a single Coy, without any Inf support, resulting in a corresponding high amount of casualties. There were also instances where the Bn had to perform platoon-sized patrols, where then just one (or none) of those soldiers returned to post.
The unit diary and the personal accounts of a Veteran of the Bn's 3rd Coy hint towards a good number of senior officers (namely von Stolzmann, as well as other officers) not caring about their soldiers' lives at all. Many of these officers saw their troops as consumables/disposables that were needed (and could be wasted) to achieve their tasks.

While weaker engineer Bns (with a lack of hvy weapons) usually received Inf support, other engineer units lacked that support, where they then had to cross rivers under fire (just supported by scout cars of the recon detachments), on some occasions, resembling combat engineer roles. In contrast, motorized engineer Bns were quite often well equipped and very well able to act as combat engineers, even though it wasn't their prime role.
Still, in general, only the mountain engineers, the specialized assault engineers (Sturmpioniere), the engineers in tank/tank grenadier units and the Parachute engineers were supposed to carry out combat missions.

Confusing? Too many details?
Maybe, but the preceding posts about the replacement regime demonstrate that the German reinforcement system appeared to be pretty complex. During early stages of the war, it enabled the Germans to ensure quality training and procedures. During 1944 it seemed to have contributed to the confusion in the supreme HQ, where Hitler started to shuffle around units that didn't exist anymore, were understrength or in the process of reforming, eventually.

My 3874624 cents