I refer you to my comments on the linked post.
The OP said it - virtually all adjacent industrialised areas were linked by rail. In the game, only a few routes over mountains and through jungle would not have such connections.
So the only use for markers I can see is for damaged links via interdiction i.e. bombing. Otherwise assume all tts are connected by rail. I never really understood the implication in the original game design that soldiers marched to the battle zones and that tanks drove there.
Generally I favour unlimited non-combat rail movement between friendly tts. It’s much simpler and doesn’t need counters or record keeping. One dynamic it changes is the relative value of armour, since this now travels at the same rate as infantry - the speed of the trains carrying them.
The other main counter argument is the relative movement of ships and aircraft. If a turn allow a train to rail artillery from Berlin to Moscow, how far should a ship be permitted to travel in the same turn? Should ships have any limit on their movement range? My solution is that every ship must demonstrate that it passes from, through or to a friendly port to refuel every turn. What’s to stop Japan loading up 10 transports and dropping them off in California? Why, the US Navy of course. The same thing can be applied to aircraft; rather than a maximum range peer turn, they must demonstrate fuel stops at set intervals on a turn. These idea also require more rules regarding enemy interception, radar range and so forth.
In general these rules mean many more units getting into battle per round. There is much less of units stalling in “mid move”, something that virtually ruined 1914 for the Central Powers until the revised rules came along.
