Using Ag3 tamplates sometimes give you the ending in colision problem. I found a simple solution. I open MSTS Activity Editor check the starting poing and run a check. You will get the consist in colision errors. Read the errors and you will see the consists names in its numerical names. Go in the Activity Editor screen and find those consists and most of the time just grab the consist and pull it foward untill the last car makes it past the siding marker. If the consist is too long just right hand click select properties and edit the consist to fit the siding.
I also found static consists stacked on top of each other. Its a matter of editing in the Activity Editor.
Thanks,
Glenn