a lay up is where trains go overnight and shit, waiting for the other train to pass on their rail,etc
numbers are the numbers you seen on a freight train
this is more of an artistic photo, but these are the numbers people talk about not going over, dont go over them beacuse thats how the yards/workers etc. identify what theyve got in their yards also, a train must be takin outa service if it has no numbers so your only hurtin yourself if you go over emhttp://www.fotango.com/p/eba00355480f00000015.jpg'>