Pic: BARNUM Saloons being worked on in G.C’s new Dukinfield Works – near Manchester
Edwardian Barnum Buffers and Buffer Mounts ~
When first designed ~ by the Great Central Railway in their new works at Dukinfield, and fitted to the production run (AD1910/11), the actual buffers – as seen on G.C. publicity photographs – were in round format. The Buffer mounts were fitted to the crossbeams with 3 sturdy bolts. This is borne out by the remaining presence of those 3 original bolt holes.
These 67 foot carriages were immediately busily employed – on holiday traffic in season and 3rd class dining car service out of season. Working practice at some point dictated the need for change. With no record available of when the change began, the equipment now present shows 4-bolt mounts and oval buffers.
Pic: Cross-section of the original buffer assembly – of eight specific elements with diagram items 5 & 6 consisting of 17 steel discs around which are sandwiched 19 rubber bushes for impact absorbance.
As this was far from merely a cosmetic change, it is possible that – because of the length of these carriages, even slight track curves risked interlocking of buffers, leading to a high risk of derailment. Probably the redesign and fit was undertaken in batches between High and Low-season. Alternatively, more likely, this may have occurred when the G.C.R. was taken into LNER ownership at the time of the ‘Big Four’ mergers in 1923/24. Their preferred design was oval, so round format buffers may not have been compatible.
Obligatory Safety checks ~
The integrity of Buffers, Mounting Blocks and ancillary shock-absorbers is crucial for in-service use. Hence the detailed application of ‘crack-revealing’ chemicals was required. This revealed hidden crack damage, threatening danger to passengers. Two new castings (these are ‘handed’ for left or right-hand use) needed replacement. Wooden cast patterns were required for an ‘iron master’, followed by fine machining to ensure their reliable and smooth operation.
Pic: Newly Cast Buffer Mounts awaiting fitting
Not your modern-day approach to fittings ~
Nowadays, we expect much metal-to-metal contact is secured by welding. In Edwardian times, especially as the buffer mounts were castings, this technique was not employed. In addition, heavy use and loose couplings meant some considerable strain in this vital area. Not having access yet to modern materials such as Polyurethane, the original G.C. Drawings show a now-surprising material applied to reduce pressure strains. This was Leather. We have therefore adopted the same techniques – of cured leather between the crossbeams and the buffer support plates and mounts. Casual glances will not betray its presence, and the leather has been treated to modern standards too.
Pic: Fitted Buffer Mount on Carriage No. 228
Edwardian concerns over the integrity of wooden carriages in accidents ~
As a side-light on railway safety concerns of the period, the higher speeds then being achieved by developing steam technologies increased the risk of carriage ‘telescoping’ under accident stresses. Possibly the oval buffer design could help minimise the risk, but the speed and weight of carriages (still wooden-bodied) suggested that serious improvements in carriage end design should be sought.
Great Central thus embarked on radical ideas, such as ‘carriage ends with teeth’! The picture helps grasp the concept: metal interlocking teeth – when meshed under accident pressure were designed to prevent telescoping, and, it was hoped, deaths from carriages zig-zagging off the track and down embankments.
Pic: A G.C. Suburban carriage No. 836, carrying trial buffer beam additions. This picture appeared in an issue of the Railway Engineers’ Journal dated December 1915. There is a second carriage, similarly treated on the track behind.
It seems that physically altered carriages were not put to the test. At least there is no published report we are aware of. However, G.C. report that the weight of metal, sufficiently robust to stand the supposed stress, weighed in at around 2 tonnes per carriage (4 pieces per carriage). With between 5 and 8 carriages per train, this added considerably to the tractive effort required of an engine. We suppose that, not being ‘things of beauty’, they were not considered attractive enough to the passengers either. The idea was dropped.
Improved ideas on train integrity reduces the risk to passengers ~
The ‘Modern’ response to the risk is to adopt ‘close-coupled’ carriages, thus changing the appearance of and experience in a complete passenger train, where all cars move off at once. The momentum of each succeeding carriage assisted the steam engine to ‘get away’. However, close-coupling requires today’s engines to produce greater power from a standing start than was formerly the case.
The ‘new’ close-coupling’ idea also minimises the effects of ‘heavy shunts’ that have cracked two of the castings on our first Barnum – as reported above. Cracks such as these are usually invisible & need special chemicals to reveal their presence. Those of us who travelled by train in the 1950’s / 60’s may well remember the sound of the ‘Wheel Tapper’ striking the wheels when stopping at major stations along your route. Just like bone china, a hidden crack betrays a dull sound. Not a technique you can apply to Buffer Mounts!
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