High speed 4 wheel vehicle suspension developments
In the mid-1960's fundamental research was being undertaken by R&DD at the RTC into the action of wheel on rail and the role of vehicle suspensions.
The suspension fitted to the majority of the four-wheel goods wagons of the period dated back to Victorian times and whilst it was acceptable for the rough and tumble of the steam railway and the slow speed trains which were the norm, with the advent of diesel and electric traction the limitation in speed of this primitive suspension was all to obvious.
Although there had been some new designs based on UIC standards in Europe i.e. friction link, double link and long link, these all relied on leaf springs for their vertical control and the friction in the links for lateral control. When the links were new and unworn their friction had a damping effect on lateral oscillation, but as the links wore so the damping effect decreased. Oiling or greasing the links would similarly reduce the friction and hence increase the tendency towards lateral oscillation.
All photos are the Author's unless otherwise indicated
|Conventional leaf spring suspension - CCT|
|UIC double link suspension - COV-AB|
There were numerous derailments of these vehicles mostly due to bad riding characteristics, in particular the Palvans were notorious (and 100 of them were fitted with UIC long-link suspension in 1966) as were the Cemflo cement wagons (see below) and the Blue Spot fish vans, but the mechanism of instability leading to derailment was not really understood.
|The result of a Palvan
derailment near Rugby Central in 1961
With the completion of the RTC at Derby in 1964, various engineers were brought together and began to address these problems in a scientific way. The instability of the vehicles brought about by the higher running speeds was investigated and a one-fifth scale model of a four-wheeled vehicle with a novel suspension was built and tested on a similar-sized roller rig. The suspension allowed lateral and yaw flexibility between the wheelset and the frame for the first time and incorporated lateral hydraulic damping.
Following these successful experiments, a full-sized
version of the roller rig was constructed and in 1966 the
four-wheel High Speed Freight Vehicle (HSFV1) was completed. This proved to be stable at up to
140 mile/h when tested on the roller rig.
HSFV1, Departmental running number RDB511023, regularly performed at 100 mile/h, both tare and laden, whilst under test on the main line. Its suspension had two vertical coil springs and two vertical and one lateral hydraulic damper at each corner of the vehicle, together with a yaw control rod on each axlebox. It could carry various rail packs enabling it to be loaded to a variety of different states.
This concept was the fore-runner of the railbus chassis, but more importantly results from various tests with HSFV1 allowed the wheel/rail interface to be better understood and this played a major role in the development of high speed operations leading to the design and build of the experimental Advanced Passenger Train (APT-E).
|Inside the Advanced Projects
Laboratory showing an APT-E bogie on a roller rig
|HSFV1 in the yard at the RTC in
the 1980's in its original rail blue livery
|An earlier view of the Advanced
Projects Lab and the roller rigs in the pit. It was on these rigs that the
HSFV1 was tested
|HSFV1 in the yard at the RTC in March 2005|
|Still retaining its original owner's name|
|A close up of the revolutionary suspension|
|The Leyland Experimental Vehicle used a similar suspension - pictured on the NNR on 11th July 2009|
HSFV2 was not built but following the disastrous derailment of a Cemflo wagon at Thirsk on 31st July 1967 (in which accident the prototype diesel DP2 was written off) the suspension was improved and re-built in 1968 as HSFV3. It is not clear what happened to this vehicle.
|Cemflo fitted with HSFV3
suspension in the yard at RTC around 1970
|A close up of the suspension
High speed stable running was a great advantage in the days of wagonload traffic as the goods would still be on the pallets at the destination rather than spread all over the floor of the wagon, as they often were with friction link, long link suspension and other variants - even at 75mile/h maximum, since these type of suspensions could readily not control lateral movement nor hunting.
After the initial test periods HSFV4 was utilised for general test work and had a flat roof added with an access ladder from within the vehicle. In this form it became a very useful van for carrying various equipment around the country in connection with OHLE and other testing work and was lettered 'Auxiliary Testing Vehicle (HSFV4)'. A bit of a comedown after its pioneering origins although it meant test trains could get to and from site at line speed.
All photos are British Rail unless otherwise indicated
|HSFV4 at the Old Dalby test track in the mid-1970's. Note the handrail for the roof access ladder projecting from the roof.|
|HSFV4 on a test train at
Llanwrst on the Conway valley line - HSFV1 is on the rear - October 1976
|HSFV4 at the Old Dalby test track used as an auxiliary test vehicle for static OHLE testing pictured on an overnight test c1977.|
|HSFV4 in the company of the
Drewry Car at the top of the Widmerpool straight at the Old Dalby test track
in the summer of 1980. Note the logo 'Auxiliary Testing Vehicle (HSFV4)'
|A view of HSFV1 and Lab One taken from the roof of HSFV4 at the Old Dalby test track in the mid-1970's|
|At the RTC in its later Research
livery in February 1983. Note the corner of HSFV1 on the left.
|HSFV4 at the Eden Valley Railway
on 25th February 2006 looking a bit worse for wear. From its livery it would
appear to have spent some time with the S&T's 'Satlink' fleet. For more
info on its present state and its post-R&DD history look
Although they were excellent riding vehicles in the railway of the day they were viewed as experimental only and far too expensive for widespread adoption. It was also thought that the sophisticated suspension would not stand up to the daily rigours to which freight vehicles were subjected.
However in the late 1970 these experiments resulted the high speed freight vehicle 'production' design. It was fitted to ten covered air braked vans (COV-AB) built at Shildon and was known as HSFV5. It consisted of a long double leaf 'Taperlite' spring suspension with hydraulic dampers inclined at 45 degrees to control both vertical and lateral movement *. It also replaced the nested springs with rubber auxiliaries. On test these vehicles were capable of stable running at up to 90 mile/h but in service were limited to 75 mile/h due to them running with other UIC long link suspension vans.
One of them was converted for use on the Tribometer train and numbered RDB999900. Another was used by DM&EE then Serco although the remainder of the batch were converted to standard after a few years. Both the Departmental ones survive to this day at the Nottingham Heritage centre, Ruddington.
I remember as a young recruit to the Field Trials section in R&DD being given the job of inspecting these vehicles in the field. I would travel to the relevant depots and give them the once over. Places visited included London - Kings Cross (York Road) and Camden, Leeds Stourton and Manchester - all gone now.
The design was not as successful as HSFV4 due to the shorter wheelbase and ultimately a new version HSFV6 was introduced and fitted to 100 COV-AB's in 1976.
HSFV1 survived until recently in Serco stock at the RTC as a prime candidate for preservation based on its important role in the development of the APT. However the NRM seem not to be aware of its importance in railway research history, preferring to concentrate on steam engines and the more glamorous aspects of preservation.
In a magnanimous gesture it was offered by Serco to the APT-E Support Group for preservation in the local area and on 14th May 2010 it left the RTC for pastures new
It is now at the Electric Railway Museum in Coventry, where it is being restored.
In May 2010 the NRM decided that it would eventually go to Shildon to be displayed alongside the APT-E.
HSFV4 was still extant at the Eden Valley Railway in February 2006 where it is to be restored to its former glory.
* Modern Railways -September 1976, 'Taperlite: a new suspension for air-braked freight wagons', pages 342, 343.
Other developments in 4-wheel wagon suspensions
|BSC pedestal suspension
P Garland collection
Gloucester Floating Axle suspension
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