The Structure Gauging Train (SGT)

The present SGT had its beginnings in the mid-1970's. Several experiments were carried out utilising the four-wheeled Wickham Self-propelled laboratory (sometimes known as the Elliot Track recording car). Using a dual-triangulation system  with lights and cameras this optical method was a big improvement over the existing ways of gauging. It was trialled at Old Dalby.

Wickham car

This is view of the Wickham car with the solebar-mounted equipment was taken at Old Dalby

Author's collection

SGT early

Here's a close-up

Author's collection

The work pioneered at Old Dalby with the Wickham lead the way for the building of the special Structure Gauging Train in the early 1980's. It was completed for the Director of Civil Engineering in the summer of 1986, the project having been in the development stage for many months.

A specially-built four wheel structure-gauging optical vehicle, ZXQ DC460000 based on a steel carrier chassis, was formed as the middle car of a 3-vehicle formation. The two outer coaches were RDB975081 ( formerly Test Coach Hermes converted to a driving trailer vehicle and re-numbered DB975081) and RDB975280 - (formerly Test Coach Mercury) became DB975280 and housed computer data collection and staff facilities. The two vehicles had previously been used extensively by the Train Control Group at the Mickleover test track and elsewhere from the early 1970's. 

Early days

The SGT on trial at the Old Dalby test track in 1985 with DB975081 nearest the camera, then DC460000 and DB975280 at the back.

BR Official

SGT Nov 85 The SGT pictured behind 47305 near Stenson Jcn in November 1985

Phil Eames

Driving trailer

A close up of 'Hermes' DB975081 in the RTC yard - note the class 24 'Experiment' in the background

D Bower

SGT June 92 The SGT pictured in December 1992 in the newer livery passing Elland being propelled by 47976

Phil Eames


The train is shown here being calibrated under the gauging rig in the yard at RTC in 1991

Author's collection

Optical car A closer view of the optical car

Author's collection

Following major changes within the Research Division in the late 1980's the SGT was transferred to the DM& EE and then to Railtest.

The present SGT is operated by DB Schenker on behalf of Network Rail 

Mixed Serco 1988

Here it is at Old Dalby heading south in the company of other Serco test coaches after a publicity shot in 1998


Inside Stanton tunnel The SGT at work in Stanton Tunnel in the late 1990's - this time in Serco livery - showing its radiating lights gauging system to good effect



The SGT in the yard at the RTC in 1999 showing the optical car in black-


Derby The new version consisting of locomotive 31233, DB975280, DB975081, DC460000 and DBSO 9708 and 31459 on the rear pictured on the Goods Road at Derby on 19th September 2008



A close up of DB975081 formerly Test Car 'Hermes' now no longer a driving trailer.


Optical car A close up of DC460000 - the optical car - now using laser technology but soon to be replaced


DB975280 A close up of DB975280 formerly Test Car 'Mercury'


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