sentences:  The Class 172/2s and 172/3s used by West Midlands Trains resemble the , , and "Electrostars" by having end gangways to allow access between units.These trains have a maximum speed of .The Class 172s feature BSI (Bergische Stahl Industrie - Autocoupler) couplers which allow them to work in multiple with , units and most other units with the same coupler.