Railcare has been awarded a contract by Porterbrook to overhaul and adapt nine of their Class 156s so that they are able to meet the Passengers with Reduced Mobility Technical Specification for Interoperability, which comes into force from 1st January 2020.
This work will guarantee the long-term future of the Class.
The company, based at Wolverton, is also to overhaul Class 153s and look at reconfiguring them back to fixed two-car units.
Porterbrook say they will explore the possibility of making the 153s compliant with the disability regulations but, because of the amount of work needed on a single car train, it was difficult to make an economic case for the work.
Unless the work is carried out the 153s will have to be withdrawn after 2020.
Such a fate is already waiting for the Pacer units, after it was decided that modifications would prove too costly.
The first 156 will enter Wolverton in May 2012, with the last one expected to be released to traffic in July 2013.
The single car 153s were originally two-car class 155s, but were converted to class 153s in the early 1990s.