While the vehicles appeared externally similar to Class 127 vehicles, the biggest difference being the Class 115 TCL vehicle had a slightly different window layout than the Class 127 TSL vehicle, with one full size window being replaced by two half windows where a bulkhead divided the first class area into smoking / non-smoking.
Internally they had improved seating, furnishings, lighting and wall surfaces, due to the work of the BTC Design Panel who wanted to remove the bus type atmosphere from the sets.
This is the first class.
This first view of a second class has an unpatterned moquette (the scan has added the dots).
This view of a second class non-smoking saloon shows moquette that was also used on the Class 126 Swindon units built for Ayrshire.
Over the years the sets had a variety of buffers, including cut, oval and large round. In 1981 some power cars were fitted with power sanders to aid adhesion.
Here are details of some of the many modifications made to the class, detailed in LMR Traction Bulletins.
Issue 4 - October 1972
Issue 36 - May 1983
Issue 39 - August 1984