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Pullman gangways and buckeye couplings.
Posted: Thu May 02, 2013 7:09 pm
by 1H was 2E
Readers will be probably be aware that where passenger trains fitted with screw couplings and BS gangways were involved in collisions, telescoping, often with the underframe of one coach cutting through the body of the next just above floor level, occurred and also coaches not being kept in line, and overturning or separating sideways. To prevent this, the RI strongly advocated the adoption of buckeye couplings. LNER enthusiasts will quickly point out that their railway adopted these as standard at an early stage. However, it seems that buckeyes were only fitted to gangwayed coaches by that railway, and into BR days non gangwayed coaches (and indeed gangwayed DMU) were still being built with screw couplings. Now I know a few GUVs were later fitted with buckeyes (with the floor plate of the Pullman gangway to provide buffing) so it's possible to do but does anyone know why it wasn't done? And does a Pullman gangway require a buckeye? The GNR used Pullman gangways and I wonder whether this also meant the similarly early adoption of buckeyes by them. It might seem that the driver of fitting buckeyes was adoption of Pullman gangways rather than safety considerations.
Re: Pullman gangways and buckeye couplings.
Posted: Thu May 02, 2013 7:24 pm
by Trestrol
Can't answer your question but i have a little bit of trivia to do with BS gangways. In the late 70's early 80's BR started a program of fitting gangways to non-corridor DMU's. instead of making new gangways they stripped the gangways from LMS BG's and GWR siphon G's and fitted them to the DMU's.
Re: Pullman gangways and buckeye couplings.
Posted: Thu May 02, 2013 8:04 pm
by Saint Johnstoun
The name Pullman Gangway is applied to all corridor carriages fitted with buckeye couplings as the design was first generally applied to Pullman Car Co. Stock in the USA. The buckeye couplings produce a 'close' coupling and therefore the gangways are short to suit; side buffers are not required, but in the case of the UK these were fitted and retracted when the buckeye couplings were in use. They were drawn out and clamps fitted over the top of the shanks to prevent them retracting when coupled to ordinary stock with screw couplings, the Buckeyes used in the UK could drop down to reveal a coupling hook. The half round spacing clamps were attached to the solebar by a chain and hung down when not in use.
Gangways used with screw couplings were longer and usually of the concertina type, and were a different profile to the Pullman ones, so gangway adaptors had to be fitted where different types of stock were coupled together.
Only Gresley Pacifics, A1 and later A3/A4 had buckeye couplings on the tender rear to suit the Pullman gangway fitted to the corridor tenders when attached.
Re: Pullman gangways and buckeye couplings.
Posted: Thu May 02, 2013 9:17 pm
by JASd17
[/quote]To prevent this, the RI strongly advocated the adoption of buckeye couplings[/quote]
The who? Which generation?
John
Re: Pullman gangways and buckeye couplings.
Posted: Thu May 02, 2013 9:25 pm
by 1H was 2E
Sorry Railway Inspectorate. Trying to save space. Broadly, during the Grouping period.
Re: Pullman gangways and buckeye couplings.
Posted: Thu May 02, 2013 9:51 pm
by 65447
The term 'buckeye' to automatic centre coupler is akin to 'Hoover' to vacuum cleaner - it is a variation and one of several similar and competing designs. The GNR originally adopted a different type, the Gould coupler, before changing over to the buckeye a few years later (c1889).
The 'driver' was the combination of the two - coupler and vestibule.
As is stated, it is the automatic centre coupler that holds the vehicles together tight and also provides some of the buffing - no side buffers being needed provided that all forms of motive power and rolling stock are fitted with the same type of automatic centre coupler. The Pullman Vestibules also had a buffing plate as the base. The type adopted for use in Great Britain was the 'drophead' type, so designated because the buckeye could be dropped through 90deg to expose a standard coupling hook, with the coupling links stored separately on the headstock.
LNER Pullman Vestibuled carriages only required the retractable side buffers for coupling up to locomotives and to vehicles fitted with coupling hook and either loose links or screw links. Some LNER carriages were still built with the British Standard (BS) vestibules/gangways, predominantly for those used individually or in sets for through workings that had to be regularly coupled with 'foreign' stock or sometimes in workings comprised of pre-Grouping stock, and also of course the offset standard gangways for PO vehicles.
It was the close coupling that permitted the use of the Pullman vestibules, which did not need clipping together as did the BS gangways, and the latter had to be fitted with the adaptor mentioned to fit with the Pullman type.
The correct LNER term is Pullman Vestibule. In the illustration below, taken from an Appendix to the Rules and Regulations and Working Time Tables, the Pullman Vestibule is omitted (as are the buffer heads) so that the remaining components are more obvious.
Re: Pullman gangways and buckeye couplings.
Posted: Thu May 02, 2013 10:04 pm
by 1H was 2E
Thanks. Interesting word, "vestibule". LMS used it to describe opens - eg VF VQ. but not side corridor stock. If couplers are not fully lifted (they are HEAVY) so that the locking pin doesn't engage the result can be a divided train. Not that uncommon in the early 70's.
Re: Pullman gangways and buckeye couplings.
Posted: Fri May 03, 2013 9:07 am
by Bill Bedford
1H was 2E wrote:However, it seems that buckeyes were only fitted to gangwayed coaches by that railway,
Yes but….
The NER 49' arc roofed coaches were initially build with fixed knuckle couplings (and I can't remember which type) and small buffers at 3'6" centres. These were replace by normal screw couplings relatively quickly, presumably because these rakes were relatively fixed in formations and so they were not able to be mixed with other stock.
Now I know a few GUVs were later fitted with buckeyes (with the floor plate of the Pullman gangway to provide buffing) so it's possible to do but does anyone know why it wasn't done?
The faceplace fitted to these coaches was not intended to take any buffing forces, they were all taken by the coupling itself. All the faceplate did was to prevent a gangway swinging about and damaging the end of the non-gangwayed carriage, or loco.
And does a Pullman gangway require a buckeye? The GNR used Pullman gangways and I wonder whether this also meant the similarly early adoption of buckeyes by them. It might seem that the driver of fitting buckeyes was adoption of Pullman gangways rather than safety considerations.
The two have always gone together, mainly, I suspect, because it would seem defeat the object to have an automatic coupling but still have to manually connect the gangways.
Re: Pullman gangways and buckeye couplings.
Posted: Fri May 03, 2013 1:05 pm
by 60800
Not being able to tell on inspection due to a lack of knowledge on the subject, I have read that there is an exception to this combination of buckeye and type of gangway used, albeit with (as far as I know) only one 61'6'' Gresley teak. I forget the number and diagram, but the one currently crammed in the 'Flying Scotsman' exhibition at York is said to not have the correct listed gangway type. I'd appreciate it if someone could enlighten me on this as to whether it's a mistake in preservation, or if it ran in LNER / BR service with the incorrect gangway.
Re: Pullman gangways and buckeye couplings.
Posted: Fri May 03, 2013 5:00 pm
by Saint Johnstoun
I think you will find that the profile of the GNR/LNER Pullman gangways was slightly different to that used on the BR Mk1 stock and from memory I think that sometimes a BR type gangway was fitted as a replacement to pre nationalisation stock. This may be the case here but I need somebody else to confirm.
Despite the slightly different profile the two types could safely be coupled together.
Re: Pullman gangways and buckeye couplings.
Posted: Fri May 03, 2013 6:33 pm
by 60044
The design of the underframe end is completely different between screw coupled and buckeyed vehicles, at least in terms of LNER carriages, so I think any upgrade would mean major rebuilding of the underframes. This why the LNERCA is shortening a standard 61'6" underframe, which can take buckeyes and Pullman gangways, for ECJS 189 rather than try to upgrade the 51ft underframe that it currently sits on.
Don't know about Mk 1 GUVs, but I suspect they had more or less standard Mk 1 underframes so were easier to convert.
Re: Pullman gangways and buckeye couplings.
Posted: Fri May 03, 2013 6:47 pm
by Saint Johnstoun
The Mk1 underframes were all designed for use with buckeyes but equipped with side buffers and screw couplings where necessary. The GUVs weren't the only Mk1s to be rebuilt. There were some Mk1 POS vehicles built with offset gangways and screw couplings for use in existing TPO trains but these were later converted.
The buffers would also have to be changed on conversion, to the retractable type with saddles provided when coupling to locos or other non buckeye stock was required.
Re: Pullman gangways and buckeye couplings.
Posted: Fri May 03, 2013 7:59 pm
by Trestrol
Blackout60800 wrote:Not being able to tell on inspection due to a lack of knowledge on the subject, I have read that there is an exception to this combination of buckeye and type of gangway used, albeit with (as far as I know) only one 61'6'' Gresley teak. I forget the number and diagram, but the one currently crammed in the 'Flying Scotsman' exhibition at York is said to not have the correct listed gangway type. I'd appreciate it if someone could enlighten me on this as to whether it's a mistake in preservation, or if it ran in LNER / BR service with the incorrect gangway.
Do you mean it has a Thompson style Pullman gangway rather than a Gresley style Pullman gangway. It was disscused here on the model railway section.
viewtopic.php?f=3&t=7183&start=315
Re: Pullman gangways and buckeye couplings.
Posted: Fri May 03, 2013 8:02 pm
by 60800
Ah that was it - thanks
Re: Pullman gangways and buckeye couplings.
Posted: Fri May 03, 2013 8:18 pm
by melton
It’s worth pointing out that the Southern Railway’s electric Pullmans (5BEL and 6PUL) didn’t have Pullman gangways whereas their steam hauled Pullman (and other main line) stock did. Maybe the fear was of the train running into something hard – i.e. it’s own derailed locomotive.