POP train

This test train originally consisted of two skeletal cars (PC3 - RDB975634 and PC4 - RDB975635) each having one mock up power bogie (P) and connected with an unpowered articulated trailer bogie (0) in between hence the nickname 'P-O-P'.

It was used from September 1971 as a test bed to prove the APT-E suspension, tilting and braking systems.The 'Power pumps' were only mock-ups, although similar externally to PC1 and PC2 in the APT-E unit minus cabs, and the whole set had to be hauled by a locomotive.

Later the P-O-P train was modified with an APT-P vehicle (Laboratory 8 - 'PILOT' RDB975636) being built and formed between the original two vehicles, which were re-mounted on revised articulated bogies and given body cladding.

The three vehicle set then performed bogie and ride research work, mainly on the West Coast Main Line.

Following the abandonment of the APT project, all three vehicles were scrapped in 1985.

The set was eventually formed as follows:

  • Number: RDB975634 - RDB975636 - RDB975635

A great deal of testing was carried out at the Old Dalby test track in connection with the APT development programme using POP train.

On 10th January 1973 a test train heading north on the test track 'ran out of road' whilst carrying out a high speed test with the 'POP' train and finished up 'on the floor'. Rumour had it that the brakes on the 'Peak' were incorrectly adjusted and the decision to apply the brakes was left until the last second.

For more information and pictures look here

Pictures courtesy of Kit Spackman except where otherwise credited

The original POP train passes Melton Junction en route to the Old Dalby test track


The Research Division, Clayton Class 17 loco No: 8512 sets off for Asfordby from the north end of the test track on 14th October 1971.

Jack Hooke

Another view at Edwalton at Old Dalby

Jack Hooke

POP train on the Widmerpool straight at Old Dalby


POP train in its second guise with panels covering the bare frames pictured in the RTC sidings

Close up inside the R&DD Test Hall

In RTC sidings with Laboratory 8 'Pilot' in the formation

Lab 8 'Pilot' in RTC sidings

Colin Marsden

PC4 975635 at RTC on 15th February 1983

Martin Allen

At the Old Dalby test track


Main line runs

At Crewe showing the articulated bogie in the early 1970s


47314 departing Peterborough on 26th March 1979


Approaching Preston from the north in the early 1980s

Dave Felton

Behind 50028 somewhere


PC4 975635 and Lab 8 Pilot at Crewe on 9 August 1982


PC3 975634 at Crewe on 9 August 1982



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