Following the successful high speed current collection programme (HSCCP) undertaken by BR's Research & Development Division at the Old Dalby test track, the BR/Brecknell Willis Highspeed pantograph was born.  Following the extensive R&DD development programme of the pantograph, which was based on Brecknell, Willis' simple Highreach Rapid Transit pantograph, the final product featured primary air suspension, an air reservoir built into the base frame, secondary torsion bar suspension, lightweight carbon carriers, aerofoils and an aerodynamically balanced head and was capable of excellent current collection at speeds up to 160mile/h.

Here are a selection of photos of the various tests undertaken during the pantograph's development.

Click on the picture for a bigger image - all photos are the author's unless otherwise credited

After extensive trials at Old Dalby the pantograph was mounted on the R&DD Electrification Section's Lab Coach 6 'Prometheus' which was able to run under 25kV and in December 1978 undertook a week's running between Euston and Blackpool. The Lab Coach was attached to the rear of a service train and the pantograph was lowered at Preston as the line to Blackpool was not electrified.

During these on track trials, several unexpected and related problems were observed in that at around 100 mile/h when running with the pantograph knuckle trailing the pantograph's uplift force was adversely affected by the aerodynamic forces and it failed to maintain contact with the overhead wire. This was completely unexpected as during all the testing at Old Dalby the pantograph had run with its knuckle leading. Also the measured uplift forces in its normal direction were seen to differ greatly between the two carbon carriers. Something must be done!

Back at the RTC following these set backs, the pantograph underwent some fundamental design changes, especially in the area of the head which was aerodynamically balanced including modifications to the cross-section of the carbon carriers and the addition of 'tabs' to the ends of the horns. Additionally the  pantograph benefited from the then unusual step (in the UK) of having specially designed adjustable aerofoils attached either side of the apex frame.

On July 30th 1979 the modified prototype pantograph had its second test series on the main line. Mounted on Laboratory Car 6 'Prometheus'  RDB975422 at the rear of a service train, running took place between London Euston and Carlisle for a week. On arrival at Carlisle the Lab Coach was removed from the rear of the train and shunted into Upperby Yard where the rake of coaches was later placed on top ensuring that it was once more at the rear for the return journey to Euston.

The pantograph's performance at the rear of the train as the second pantograph was remarkable. It was as good as the Faiveley when leading and our pan was running on an already moving contact wire.

The 'high wire height' tests had HST super power as can be seen from the picture and ran at up to 125 mile/h between Selby Station and Shaftholme Junction on the old ECML alignment, which at the time was not electrified. Both the BR/BW and Faiveley pantographs were tested and the picture shows the latter under test in September 1979 mounted on Lab Coach 6 'Prometheus' .

First time in anger

86244 pictured in service much later, at Hademoor Crossing on the WCML. The pantograph covered over half a million miles on 86 244, but it was well looked after by R&DD staff.

Two-pan operation trials

During June 1982 an unusual HST set could be seen on the northern end of the WCML. At the time there were proposals for an electric version of the HST which would have a power car at each end of the train with pantograph raised.  There was a reluctance by the IEE at the time to allow 25kV bus bars to run the length of electric passenger trains (particularly between vehicles) hence it would be necessary to have two pantographs, both collecting current on the new train - fortunately no such restrictions apply today so a Pendolino usually runs with only one pan raised and the new IEP will be similarly operated. And that's why APT-P had its power cars marshalled next to each other.

In order to test the performance of two BR/BW pantographs at high speed on the same train six redundant Mk3 Restaurant cars were acquired and these were assembled at Derby in the following consist

PCs 43194 + 43193, Lab One RDB975000, 2xTGS, 6xTRUK and RDB975422 Lab Coach 6

Based at Craigentinny Depot, Edinburgh the train was re-marshalled during the tests to form up to a 10 car HST set. With special arrangements in place and permission from the Civil Engineers the train was tested well above line speed at up to 125 mile/h down Beattock bank through Lockerbie towards Carlisle. The formation of the train was varied during the tests to judge the affect of differing pantograph spacing on performance.

A close up of the base of the APT version of the pantograph in the static test rig at RTC. Note the hydraulic actuator on the right and the restraining wires and the air reservoir now incorporated into the front frame member. By vibrating the pantograph at various frequencies and amplitudes the optimum values of pneumatic damping and spring rates were evaluated.

In 1982 the set is pictured passing Rugeley on the Trent Valley route heading south.

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Overseas

Further development and marketing saw the pantograph being trialled by SJ in Sweden and SAR in South Africa.

An SAR test engineer climbs aboard the GEC 6E locomotive E1525 which was fitted with a BR/Brecknell Willis pantograph. This picture was taken in November 1980 on the line between Pretoria and Kimberley.

A close up of the SAR version of the pantograph. The head was approx. 0.5m wider than the UK version which lead to aerodynamic problems

Here's a close-up of the arrangement. The British pantograph needed to be mounted on a framework to raise it to enable the pantograph to reach the OHLE, which is approx. 1 metre higher in the USA than in UK.

Note the different head design for the US.

Today the pantograph and its variants are fitted to the majority of electric locos in the UK including the Channel Tunnel Shuttle locos, (among the most powerful locomotives in Europe) and to a large number of EMU fleets.  The Pendolinos are fitted with their own version as are the Eurostars (for use in Belgium).

Developments in pantograph head design, which had their roots in the High Speed Current Collection Project and were tested at BR's Old Dalby test track, have been adopted by numerous train companies and can be seen on nearly all the Faiveley pantographs in the UK.

'Acela Express power car 2001 complete with flannel clad engineer and flashing ditch lights hums past a Forest Hills Bound MBTA Orange Line Train'.

For more details of the Acela trains look here