In the absence of any up coming engine changes, I have decided to start a thread to open some discussion on the topic of land transport. This discussion is related to trying to make a viable option for trains, though not meant to be exclusively for that purpose.
As far as land transport goes... there seems to be three viable options...
1) Use the land transportable function. Which while it allows for land transport and can allow a unit to move after dropping off, is limited to 1 unit of cargo per transport. For obvious reasons this is an issue from a reality perspective.
2) Create a system of connected sea zones and create a naval "land" infrastructure system. The issue of this is that while you have the ability to move multiple units with one transport, it creates issues with being able to have transports move after dropping off units. This also creates issues related to tactical, Strat bombing and intercepting since you need to create separate "territories" for the train.
3) Abstraction of the land movement via triggers that provide additional movement to units based on the location or presence of some other unit. This option can have serious undesirable effects to the combat or non-combat phases of a turn.
So what I am asking is does anyone have any ideas that would provide for a realistic mass land transport system that; a) can transport multiple units based on capacity limits (similar to sea transports), b) can be targeted for destruction by an opponent via bombing or direct attack, c) has a system of building and construction that is not terribly confusing.
“A man can never have too much red wine, too many books, or too much ammunition”― Rudyard Kipling
You can add at least a couple points more, actually.
Especially since now the AND canals thing appears to be supported again, you can add paratroopers to the list, as long as you make a set of canals keeping the air-train on land only and avoiding it flying over enemy territories. The advantage, over land transport, is that you can transport multiple and even set specific transport costs for units, plus freeing the mechinfantry ability for something else, and you can still move on after having transported; the disadvantage is that (differently from land transport) you can't make multiple transportations on the same turn (landtransport allows you to do it, even tho, afaik, no maps use this possibility) and you have to start in the territory where it is the unit to transport (while both landtransports and ships allow you to pick up the transported unit on the move) (tho, this is a minor limit, because your air-train can complete its movement after having dropped the cargo; so you just need to position it ahead). The biggest limit of this solution is that you would be unable to ship trains (train shipping was a significant share of lend lease).
In case of paratropers, as well as mechanized, you can avoid losing this ability for other uses by simply having a (accordingly triggerful) special movement phase for train only (triggering in and out the stuff).
You can also add the possibility of having a special phase in which you consime a "train" resource to move, which is equal to a multiple of your train stock (which would be a stack of units creating the "train" resource each turn), and have a set of canals to limit movement to railways, plus a trigger removing the resource each end turn.
For several reasons, I advice simulating trains by using mechinfantry and a set of canals to restrict them to friendly-to-friendly territory moves through connections having railway lines (to be displayed on the map accordingly) only.
Useractions to build or destroy railways (canals) may be cool, but would imply having no display.
I want to add a bottomline about the fact that boardgames with trains like to represent railways like they are some sort of exceptional things you have only in a few connections, but this is very wrong. You just need to open a good atlas at the time to see that there are a lot of railways lines about everywhere (and you really need only 1 per each connection to move close to infinite trains) relevant (main exceptions being Libya, Siberia and China); so, if you are making a scenario like NWO, you can almost just let trains move anywhere. Aside from territories having no railways at all, if the game is grand strategical, the real limit is your train stock, not railways (exceptions are the side theaters of war, usually of marginal importance).
I would recommend using a movement point system, with a X maximum movement for any unit in a turn, limited by time. The movement can be through any territories with a 'Mobility' attachment or a unit which Gives NCM (non-combat mobility), by any unit which has a 'Mobility' attachment. By default, units with mobility will have Mobility=1. This means a unit with Mobility consumes one mobility point for each territory it moves through, up to the limit X per turn. The mobility points could be set per nation by global variable, or earned like resources, or purchased with PUs.
X = maximum number of extra moves per unit in a turn
Y = Available mobility points
Z = number of mobility points required per move (default=1 for each unit, but can be differentiated)
'thats the way it is' makes it neither desireable nor inevitable