I had fun with the railcraft mod, I just wish it interacted a little better with the other mods from tekkit. The longest train I made with it was over 50 cars long and needed 20 "locomotives" to move. It still never completed the 5km circuit that I had made to the various resource centers... 
At that point I just make a second or third line with shorter trains.
Or go through the painstaking work of leveling out the line to where trains only have to worry about 1 tile inclines/declines.
It is sad when even with 10 locomotives a train gets stuck on a hill WITH booster track...
If they weren't so fun to use I would just use transport pipes to get my crap where I need it. But wasting diamonds on such things is silly.
