years was widely held to be the standard during the diesel locomotives st generation with switchers perhaps  more years Of course GPs and such soon proved that  years was an underestimation for well maintained quality freight power that still had useful assignments they were suited for I imagine that  years is more like it these days although  years is still the length of lease for most leases and many locomotives are returned upon expiration   For when you have the money thats still the gold standard where passenger carriers are concerned Look at Go Transit for example or Amtraks planswish list for the future in regards to retirement dates that theyve published in recent years as they try to develop a strategy for future fleet acquisitions