73156 is the only preserved member of the class that was built at Doncaster where it was completed in December 1956. During its working career it was serviced at Doncaster (overhauls in February and November 1959), Derby (overhaul and fitted with boiler from 73158 in October 1961 and another overhaul in January 1963), Cowlairs (overhaul and fitted with boiler from 73059) and Tyseley (tyre turning in April 1967).
Motive power depot allocations.
| Date Arrived | Depot |
| December 1956 | Neasden |
| April 1958 | Millhouses |
| January 1959 | Sheffield Grimesthorpe |
| September 1960 | Derby |
| September 1960 | Neasden |
| June 1962 | Leicester Central |
| February 1963 | Woodford Halse |
| May 1963 | Cricklewood |
| October 1964 | Leamington Spa |
| June 1965 | Tyseley |
| April 1966 | Bolton |
At Neasden 73156 worked over the Great Central line where the standard workload of the Standard class 5 locomotives allocated there included hauling The Master Cutler (Marylebone-Sheffield) and The South Yorkshireman (Marylebone-Bradford Exchange).
Whilst at Sheffield Millerhouses the engine was used on services the Midland route from Manchester to St Pancras which had been upgraded and additional class 5 locomotives were required to bolster the fleet of Jubilee class engines.
By the time 73156 moved back south to Cricklewood the Peak class (later 45 class) diesels were handling the passenger trains out of St Pancras.
The last recorded working of the engine was on the Colne to Stockport parcels on 17th November 1967.
73156 was withdrawn from service in November 1967 having completed only about 325,000 miles under BR ownership. The main reason for it being withdrawn was the severe wasting of tender plating. It was sold to Woodham Brothers for scrap and arrived at the scrapyard in Barry in February 1968. It remained at Barry until October 1986.
In the mid 1980’s a small group of individuals in Lancashire formed themselves into the North West Locomotive Action Group (NWLAG) with the intention of purchasing for preservation a locomotive having connections with the North West of England. In order to progress the purchase of 73156 set up a private limited company called the Bolton Steam Locomotive Company Ltd. The purchase of the engine was completed in November 1985 and the locomotive minus a tender was moved to the East Lancashire Railway at Bury the following year.
The locomotive was stripped; an inventory compiled of components available, a much longer inventory of components required and protective attention given to the frames and firebox/boiler. Funds were raised by whatever means, but the scale of the task facing the group was such that the restoration was definitely in the long term category.
Although covered accommodation was initially provided at Bury, from the early 1990s the demand for workshop space increased and priority was given to owning groups who were more advanced or were employing contractors to undertake the restoration work.
At this time the NWLAG formed the 73156 Support Group in order to attract funds by annual subscription in addition to the purchase of shares.
As the locomotive required a tender the options to provide one was considered in the knowledge that no BR1 tenders were available. The decision was taken to build a new one from scratch which at that time had not been done before for any preserved locomotives.
Facilities were made available by a supportive enterprise and construction of the new tender underframe commenced. Also of great help was and is the beneficial advice from participation in the BR Standard Locomotive Owners Group and pooling of resources for the production of patterns and aggregated requirements for purchasing castings.
Demand for space under cover at Bury for projects with funding underwritten resulted in 73156 being moved outside, where working conditions were very difficult. Whilst some funds were raised it was not enough and with the failure of a bid to the Heritage Lottery Fund together with the slow sale of Shares meant that action was required. It was agreed that the best chance of restoring 73156 would be to join forces with a heritage railway looking for additional motive power who would assist in the completion of the restoration, in return for which the restored locomotive would be made available to the host railway for a period of years of operation.
As a result of the strong connection of the locomotive with the Great Central route and particularly with Leicester Central in 2001 a meeting was help with the Loughborough Standard Locomotives Group Ltd (LSLG) to discuss the terms under which 73156 would be moved to the Great Central Railway. As a result, an agreement was concluded whereby LSLG would act as custodian of the locomotive and provide non-financial support for the completion of the restoration of the locomotive. The Bolton Steam Locomotive Company Ltd remains responsible for financing the work including the provision of a tender. In return for the assistance and use of the Great Central Railway facilities at Loughborough 73156 will be based on GCR for the majority of the ten year period following restoration of the locomotive.
73156 moved to the GCR at Loughborough in 2002.
Work on the frames has been completed and the boiler (originally fitted to 73059) replaced in the frames to allow the small and large bore copper pipework to be completed. All the motion is in place. The boiler, complete with its new smokebox, has since been removed again for its overhaul to commence. The all new tender has had its frames assembled and is awaiting the fitment of its new wheelsets. The tank is also ready for fitting, as is all the brake gear, which has been made at Loughborough.
In August 2016 the locomotive passed its hydraulic test and steam tests resulting in the locomotive having a boiler certificate as of 26th August which is valid for seven years. It is anticipated that after seven years a review of the boiler will be undertake which may result in a number of small tubes being replaced before a further three year certificate is approved.
The boiler was lifted back onto the frames in December 2016 and 73156 moved under its own steam again in early September 2017. The running in trials identified that there was a problem with the left-hand coupling rod bearing running warm. The problem was subsequently identified as being a slight misalighnment of the coupling rod section which dated back to contract machining a decade earlier.
It is thought that the locomotive would be fully operational again soon once a replacement bearing bush is available and the alignment of the coupling rod has been corrected.
In December 2017 the frame was lifted off the its driving wheels so that the cause of the warm bearings during its running-in trials.
In January 2018 the coupled wheelset was sent to the South Devon Railway for repair. This enabled the wheelset to be reunited with the locomotive at Loughborough in April 2018 and later that month a fire was lit in its boiler once again.
The locomotive returned to traffic in May 2018.
| Home Base | Current Status | Owner |
| Great Central Railway |
Operational
| Bolton Steam Locomotive Ltd. Private company limited by shares |
Preserved British Steam Locomotives 