Lab 25 - Decapod

In the Research Division of BR in the 1970's there were several projects which utilised load-measuring wheelsets (LMW).

Several of these specially-designed spoked wheelsets were manufactured from solid blanks and were delivered to the RTC where they were strain-gauged by the author and colleagues. A special rig was set up within the R&DD main Test Hall workshop where this work was undertaken and where the wheelsets were calibrated. This was separated from the shop by sackcloth-covered wooden screens and was hence known as the 'Hessian Hut'.

One test series which I was involved with was the curving tests undertaken with HSFV1 using two of the wheelsets on the four wheeled wagon.

Information was needed on the ability of curved tracks to withstand the higher forces expected when train speeds are increased.

A contemporary account follows:

A special laboratory vehicle which could simulate such forces was developed and this report describes tests carried out both on the test tracks (Old Dalby and Mickleover) and on the West Coast Main Line. It concludes that track is generally able to carry the expected forces but that important exceptions require clarification by further investigation. It is highly desirable that further information be obtained on:

bulletComparison between the effect on track, particularly its permanent displacement, of loading with Lab 25 and the passage of vehicles at high speed.
bulletThe identification of weak sections of track.
bulletThe influence of tamping lift, and other variations in maintenance techniques, on the resultant strength of the track. T
bullethe benefit to be gained by artificially consolidating the track.
bulletThe rate at which track is consolidated by traffic, following tamping and re-ballasting

Lab 25 was built for the purpose of detailed investigation all of the above and lateral track forces, curving and rail corrugations. This vehicle was a converted Freightliner flat which was fitted with low track force bogies in place of the normal Gloucester 3-piece and had its chassis raised. A retractable LMW was fitted between the existing bogies. Onto the centre of the vehicle was built the accommodation for the crew and instrumentation and the outer ends were left open and used for loading purposes - note on the photos the rail packs which were also used on HSFV1.

 Lab 25, (RDB602150) had ten wheels and consequently, in true R&D tradition, was christened 'Decapod'.

Although the author was involved with a number of tests with the vehicle, I left the Project before it was completed.

Click on the picture for a bigger image

RDB602150 Decapod in the loop at the RTC

Colin Marsden

Decapod on a test train pictured in Crewe station sometime in the late 1970's

John Tuffs

A class 45 heads past the site of the former Etwall station on the Mickleover test track with Decapod in tow in the 1970s

Gerald Anthony

Mickleover Here it is in the company of HSFV1 at Mickleover in 1990

P Graves



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