Editing Classification yard (section)

==Unique locomotives==
[[File:Master and slave, Tinsley Marshalling Yard (geograph 5493909).jpg|thumb|British Rail Class 13 built for a hump yard]]{{Section rewrite|date=October 2024}}
Hump yards sometimes require unique locomotives, for example, where larger frames may ground. For this and other reasons, one can sometimes find locomotives specifically made or converted to work a hump yard. For example, the [[British Rail Class 13]] was converted from a pair of [[British Rail Class 08]] to provide more power than one could get with a single Class 08. The class 13s were built because of the risk of grounding with larger units like the [[British Rail Class 20]].<ref>{{cite magazine |editor-last=Bickerdyke |editor-first=Paul |title=Class 13 Tinsley Shunters |magazine=Rail Express |date=October 2015 |issue=233 |page=25 |publisher=Mortons Media Publishing |location=Horncastle |issn=1362-234X }}</ref> Special locomotives for hump yards in the US were for example the EMD TR family ([[EMD TR]], [[EMD TR1]], [[EMD TR2]], [[EMD TR3]], [[EMD TR4]], [[EMD TR5]] and [[EMD TR6]]). These are often referred to as ''[[Cow–calf|master and slave]]'' in GB and ''cow–calf'' in the US.<ref name=":4">{{Cite book |last1=Solomon |first1=Brian |url=https://books.google.com/books?id=BOfUBAAAQBAJ&dq=Cow-calf+switcher&pg=PA37 |title=Chicago: America's Railroad Capital: The Illustrated History, 1836 to Today |last2=Blaszak |first2=Michael |last3=Gruber |first3=John |last4=Guss |first4=Chris |date=2014-10-14 |publisher=Voyageur Press |isbn=978-0-7603-4603-7 |pages=37 |language=en}}</ref><ref name=":3">{{Cite book |last=Foster |first=Gerald L. |url=https://books.google.com/books?id=ZvSHlCxuyH0C&dq=Cow-calf+switcher&pg=PA10 |title=A Field Guide to Trains of North America |date=1996 |publisher=Houghton Mifflin Harcourt |isbn=978-0-395-70112-6 |pages=10 |language=en}}</ref><ref>{{cite book |last1=Smith |first1=Keith |title=Supplement to the West Somerset Railway Stockbook |date=1999 |publisher=West Somerset Railway Association |location=Bishops Lydeard |page=9|edition=5th }}</ref><ref>{{cite book |title=Industrial Locomotives |date=1982 |isbn=0-901096-44-X |page=232 |edition=6EL |publisher=Industrial Railway Society}}</ref>