Somewhat familiar...
This is, IMHO, a very decent game. The graphics and sounds are good, the gameplay was well thought-out and the idea is somewhat original.
However, there are a few draw-backs:
1) All units and terrain are based on one of your other games, also featured on NG. Although I purchased the full version of that game and actually tried to IMAGINE what it would be like to command one of those wartrains rather than blowing them up, it feels like being cheated on now it's actually here: do I have to pay all over again for the same units etc. just because I like being a train better than being an aeroplane?
2) When you were copying from your aircraft game, you should have copied the controls for the wagon dropping helicopter as well: now it is quite impossible to drop off a wagon near the edges of the map.
3) Come on: giving repair bonussen right after a repair point? That's plain silly. Perhaps my main issue here are the bonusses themselves: coal or money lying on the track? Repairs lying on the track (like: are there mechanics hiding there)? The filling stations are a much better way to go. You could have added catches to some of them for the same result as a bonus: no repairs available (out of steel/no mechanics present), no fuel available (out of coal), only a limit amount of either available (low on coal or steel)... The same 'excuse' could be used to make the station unavailable the second time you stop there. You could even have a plane blow up the station immediately after you leave as well - now THAT would be wicked :-D
Apart from that: if you are going to include a fine tutorial, it may be a good idea to mention it at the start of your instructions page as to prevent some people from giving up on your game before even playing it. The gameplay is not that hard, so you may want to have a taste and come back to the instructions afterwards instead.
Anyway, the overal verdict is very positive. I'm just a sucker for trains - and this game's creators...