help with consist editing.

[csx6063]

hello all im new to this forum. and i have some repaints of the default cars for this game. i have rw_tools. and i been trying to play around with that. now if i try to do the 4 steel coil cars on the thorny matter scenerio i can get three swapped. the three back by the bumper change with no problem. but when i try to do the first one my game will crash. is the a really easy way for a noob like me to this? i tried the scenario editor but i can't keep the cars where i want them. please help me.