A quartet of brand-new Union Pacific SD70ACe diesels sit on the "Dodo" track at the railroad's Dolores Yard on a bright April 1st, 2013. Coupled behind UP 8813 are units 8820, 8812 and 8818.
There are times when many engines, cars or cabooses are concentrated in a location. Such sites are for storage, economic reasons, active power needs or for rebuilding. For others, wear and tear have brought their usefulness to and end.
