We have discuss short lines,train symbols and numbers,etc now let's look at yard tracks and what they are use for. Why a yard? Well a railroad needs a place to sort,store cars and build trains.A yard doesn't have to be a massive size yard can be as small as one track just enough to put a train in working order.In fact I know of a short line that uses a old passing siding for a yard. Now let's look at the average yard tracks and what they are use for.For ease of this discussion I am going to give each track a number from front of the yard to back of the yard. Track one could be used for Eastbound cars destine for off layout divisions/destinations (stagging yard). Track Two could be use for Westbound cars destine for off layout divisions/destinations (stagging yard). Track three can be the cars for the industries located in our division and inter division transfer Track four can be for holding home road empties till needed by the industries for loading. Track five can be the interchange cars for (say) NS Track six can be interchange cars for (say) CSX Track seven is the "kick" track.This is where we keep "overflow" cars for any industry. To complete our yard we should have a arrival/departure track.This track should be double ended as we need a engine escape track. It is my opinion that the yard lead should be as long as the longest yard track plus two locomotive lengths.That should give us lots of head room to work our yard with.Of course don't be above using the main for a switch lead if needed..You see railroads will do that on a has needed bases such as a small outlaying yard in a small town or city that is used as a overflow holding track for several industries.You see this small yard may have a small lead between the main and yard ladder but,not enough head room to work the yard without fouling the main. A nice touch would be a "runner" track that is as long as the yard.That track is use mostly for locomotives heading to or from the engine service area and by the yard crew if we have a double ended yard. Of course IF cabooses are use then a short caboose track is needed.IMHO this track should be doubled ended so we can work both ends. ======================================================= Short line yards Again a short line may have a single track "yard" where a train can be put in working order which may include the interchange track or a old passing siding.. A bigger short line may have a 3 or 4 track yard. As far as holding "overflow" cars for industries any track will do including other industries switch leads or part of the main line that is no longer used! A former passing siding can be use as well.