trench railways, were used during the glory days of trenches, or known as ww1, to deliver fresh troops, and supplys, to armys locked in trench ridden battles. This one, engine #3, nicknamed "Lil Tim", is currently delivering food, and 5 passenger cars, full of fresh troops, to the african trench front, in the 5th madridian war.
also if your wondering, no, its not a war crime to hit a trench train, but it wont matter because more will come, or the artillery shot or bomb will just be shot at by the trains AA guns.