Ive played d21 several times, restarted it twice at turn 30 and 50 just because I had totally mismanaged my rail building.
A lot of the advice to get on track pardon the pun, was from aars and I believe Slith and Larrys advice in several threads.*hat tip*
You should concentrate rail units, I had best luck with stacks of 3. If I remember correctly you can get 3 stacks of 3 and a stack of 4 concentrating your Italian rails repairs units with the German( when you can get them there).
Pick routes- take a really good look at whats ahead and where you think you'll need them best, one for each army grp. as a primary line you want repaired and stick with them( you can start repairing branch lines another routes later). The first 12 or so turns there wasnt much repair but for some reason there after it went fairly well.
I was getting 4-5 hexs ( or more) repaired ahead of 2 or 3 of the 4 stacks per turn, its random re; which stacks will reapir each turn.
I didnt see much if at all, any hexs repaired behind or further way than what I sat them directly in front of, as close to then line/hex you want repaired as possible.
Theres a probability factor per repair unit per turn, so concentrating them is key, gets you better odds per stack on repair where you want it. Also another tidbit I picked up later, disband the RR unit in Finland as its not much use as it seems to increase the probability for the other units because there are fewer.
When you've got a main line for each of your Army Grps, then go back to the nearest next broken line you want build to supply another area of the front, keep the rr units concentrated, always.
I just went back and looked; at turn 70, Feb. of 42, I was doing pretty well, had 3 main lines and was working on branch lines, its doable.
< Message edited by carll11 -- 11/5/2020 10:10:14 PM >