slip coach

from WordNet (r) 3.0 (2006)

slip coach
    n 1: a railway car at the end of the train; it can be detached
         without stopping the train [syn: {slip coach}, {slip
         carriage}]

from The Collaborative International Dictionary of English v.0.48

slip carriage \slip carriage\, slip coach \slip coach\n.
   a railway car at the end of the train; it can be detached
   without stopping the train. [British]

   Syn: slip coach
        [WordNet 1.5]