The class 126 DMU was built especially for Scottish Region services, and as such hold special interest for the SRPS. All the units spent their entire working lives in Scotland. The unit is the only surviving example in the UK of the higher specification Inter-City type. The centre trailer vehicle is unique in that features both first and second-class compartment accommodation. In addition we have an as yet unrestored buffet car from the original 1956 batch, one of only two surviving DMU catering vehicles and as such, these trains were felt to be an important part of Scotland's railway heritage. The last of the 1959-built versions ran in 1983 and accordingly one was rescued for preservation at that time with assistance from the Royal Museum of Scotland. It is now an important part of the SRPS's collection of historic railway vehicles at Bo'ness in West Lothian.

Designed for a life span of 15 to 20 years, by the 1980s the class 126 units were looking decidedly run down. Each unit had covered over 2 million miles in service. Once-modern interiors had suffered from the wear and tear of millions of commuter journeys - and at the hands of vandals. By this time Scottish Region had begun to take delivery of the first of the 'Sprinter' type units and the requirement for the 'first generation' units was greatly reduced. Due to mechanical differences in their construction, the class 126 cars were not compatible with other DMU types, and so were selected for withdrawal, the last two units surviving in service until January 1983. The best of these vehicles were selected for preservation.

Full scale restoration of the train began in 2000 with the aid of a grant from the Heritage Lottery Fund. The interiors of the units were completely destroyed due to the requirement to remove the asbestos insulation to ensure the long term survival of this most interesting train.