This locomotive was built in 1930 at Derby as 6152 The Kings Dragoon Guardsman.
In 1933 the LMS was invited to send a locomotive and train to the Century of Progress International Exposition in Chicago, USA.It was decided to send an engine of the Royal Scot class, and one was selected that was due for general overhaul. The identity of this locomotive was 6152 The Kings Dragoon Guardsman. The coupled axleboxes were replaced with larger ones, based on a GWR design, and the bogie replaced by a De Glehn type, also derived from GWR practice. Springs and spring rigging were also updated, and the boiler replaced. The rebuilt locomotive assumed the identity of 6100 The Royal Scot with (on its return from the USA) an enlarged nameplate with details of its appearance at the exhibition. It retained this identity after its return from the USA. Whilst in America the engine went on an 11,194 mile tour of North America including crossing the Rockies.
The locomotive was rebuilt in 1950 with a taper boiler, double chimney and new cylinders following the success achieved with the two Jubilee class locomotives (45735/6) rebuilt in 1942.
BR motive power depot allocations since 1948.
| Date Arrived | Depot |
| January 1948 | Camden |
| November 1959 | Nottingham |
| July 1961 | Derby |
| August 1961 | Nottingham |
46100 was withdrawn from service in October 1962 whilst based at Nottingham.
It was bought by Billy Butlin of Butlins Holiday Camps and after cosmetic restoration at Crewe Works, was set on a plinth at Skegness. It was painted in LMS crimson lake livery which, although the original livery received, the locomotive did not carry it after being rebuilt (only one rebuilt Royal Scot ever carried LMS crimson lake livery and that was 6170 Royal British Legion).
As 6100 it was towed from Crewe Works to Nottingham in June 1963 by Black 5 No. 45038 and then from Nottingham to Boston by B1 No. 61177. It spent a few days at Boston shed before being taken to Skegness by an Ivatt 4MT, where the locomotive languished for 3 weeks in Skegness goods yard before being transferred to a Pickford’s low loader for the short road trip to Ingoldmells. 6100 arrived in the Butlins complex on 18 July 1963 piped in by pipers from the 1st Battalion, The Royal Scots.
6100 left Skegness for the Bressingham Steam Museum on 16 March 1971 and was returned to steam in 1972. It ran until 1978 when it became a static exhibit again. It was sold by Butlins to Bressingham in May 1989.
On 20 March 2009, Royal Scot caught fire en route to a steam gala at the West Somerset Railway. The locomotive was being transported along the M5 Motorway when a fire started on the lorry under the locomotives leading wheels.
Briefly steamed in 2009 before it was discovered that a major overhaul was required.
In April 2009 took part in the Steel, Steam & Stars 11 event on the Llangollen Railway after which it was discovered that the locomotive needed serious attention.
After sale to the Royal Scot Locomotive and General Trust (RSL>) in April 2009, chaired by enthusiast Jeremy Hosking, it was moved by road to Pete Waterman’s LNWR Heritage workshops in Crewe.
Following completion of this work at Crewe in 2015 46100 was transported to the Severn Valley Railway for running in before taking part in the autumn steam gala there. It is now back running on the main line.
As part of the 2018/19 winter maintenance the driving wheels were sent to the South Devon Railway for new tyres to be fitted.
In September 2019 it was reported that the locomotives return to traffic had been delayed following the discovery of cracking in the tender axlebox horn guides when the wheelsets were removed for transporting to the South Devon Railway. It was still hoped that the locomotive would be back in service late in September 2019.
After being moved by road, to the Severn Valley Railway where shortly afterwards it underwent light and loaded test runs in November 2019 before running under its own steam to Crewe.
The boiler certificate is due to expire in March 2022 but an extension may be applied for as this would ease the pressure in the boiler shop at Crewe in 2022.
In December 2021 the locomotive was failed whilst hauling a train on the main line near Euxton Junction near Preston.
| Home Base | Current Status | Owner |
| Crewe | Operational | Royal Scot Locomotive and General Trust |
Preserved British Steam Locomotives 