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Title: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: JayMac on April 03, 2015, 12:07:05 First balls up of the Easter weekend. The 0748 Plymouth to London Waterloo FGW HST had a carriage in the consist with Long Swing Link bogies, which are not permitted to run over the 3rd rail network.
Beggars belief that such a basic error was made. I was on the offending set and we have been terminated at Andover and transferred to a folliwing SWT service. Fortunately not to busy, but still an inconvenience. I'm chancing my arm at Basingstoke by waiting for the next FGW service to Waterloo which is nominally set down only at Basingstoke. Title: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: IndustryInsider on April 03, 2015, 12:52:43 Oops!
The diversions via Banbury all appear to be working well so far. Title: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: JayMac on April 03, 2015, 13:07:02 Grapevine tells me it may have been a clued up member of the public who saw the 'LSL' label as we departed Westbury. I'm guessing it took a while for the message to get through to the train. Good job The TM and driver were made aware before we'd got to Worting Junction where the third rail starts. Could have been fireworks!
Title: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: BerkshireBugsy on April 03, 2015, 14:21:49 Grapevine tells me it may have been a clued up member of the public who saw the 'LSL' label as we departed Westbury. I'm guessing it took a while for the message to get through to the train. Good job The TM and driver were made aware before we'd got to Worting Junction where the third rail starts. Could have been fireworks! Now bnm I'm not tryng to pick you up on your post but do I take it there is something different about the LSL bogies which cause them to foul with the 3rd rail ? Title: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: JayMac on April 03, 2015, 14:56:45 There is indeed bb.
Less clearance between bogie frame bottom and 3rd rail head. Can cause arcing, may even foul the 3rd rail with too much lateral motion. Title: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: BerkshireBugsy on April 03, 2015, 14:58:42 There is indeed bb. Less clearance between bogie frame bottom and 3rd rail head. Can cause arcing, may even foul the 3rd rail with too much lateral motion. Many thanks Title: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: TaplowGreen on April 03, 2015, 17:02:03 First balls up of the Easter weekend. The 0748 Plymouth to London Waterloo FGW HST had a carriage in the consist with Long Swing Link bogies, which are not permitted to run over the 3rd rail network. Beggars belief that such a basic error was made. I was on the offending set and we have been terminated at Andover and transferred to a folliwing SWT service. Fortunately not to busy, but still an inconvenience. I'm chancing my arm at Basingstoke by waiting for the next FGW service to Waterloo which is nominally set down only at Basingstoke. Hope you got on OK BNM? ........Interview without coffee or Easter eggs for someone next week then! Title: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: JayMac on April 03, 2015, 17:15:04 Got on okay. It was a jolly so didn't mind sliding back an hour to pick up the next Waterloo bound HST at Basingstoke.
Problems at Paddington trying to get a change of route excess fare for my return west. That's for another topic later. Don't worry I wasn't held captive for two hours this time. :) Title: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: Timmer on April 03, 2015, 17:38:20 Grapevine tells me it may have been a clued up member of the public who saw the 'LSL' label as we departed Westbury. I'm guessing it took a while for the message to get through to the train. Good job The TM and driver were made aware before we'd got to Worting Junction where the third rail starts. Could have been fireworks! Can't say I'm surprised a carriage slipped through the net with all the chopping and changing of carriages over recent months connected with the 1st to Std conversions. Was only thinking on my way up to Waterloo on the 5.50 ex Plymouth that careful checking of each set heading to Waterloo would needed to have been done. Apart from this service you were on being canned BNM, and the return from Waterloo, all looks to have gone fairly smoothly though IC13 11.00 pad-tau was held at Swindon for some reason leaving 36 minutes late. Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: JayMac on April 09, 2015, 23:43:06 I've been out snapping pictures of bogies as I couldn't find any decent images online that clearly show the differences between Long and Short Swing Links.
The things I do for this forum! :P Here's a comparison montage showing the major difference between the two types of Mk3 bogie. I've highlighted the areas on the Long Swing Link bogies that can cause problems if ran on the third rail network. Short Swing Link top. Long Swing Link bottom. (http://i598.photobucket.com/albums/tt68/bignosemac/SSL_LSL_zps0rxzn1qz.jpg) Essentially, it's a different type of fixing of the swing links to the lower frame (called the spring plank) of the air spring. Here's a technical drawing of the Mk3 (BT10) bogie which shows the position of the swing links (13): (http://i598.photobucket.com/albums/tt68/bignosemac/BT10_zpsu9wpyad3.jpg) That image taken from a 1977 publicity booklet focusing on the technical details of the High Speed Train. From the Railway Archive. http://www.railwaysarchive.co.uk/docsummary.php?docID=537 Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: Chris from Nailsea on April 10, 2015, 00:25:50 I've been out snapping pictures of bogies ... I don't think that was what bobm meant, when he suggested that you ought to 'get out a bit more' ... ;) :D ;D Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: bobm on April 10, 2015, 06:42:49 Is there an advantage to having LSL bogies? I assume there is or all the sets would have been converted to SSLs.
Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: paul7575 on April 10, 2015, 14:05:19 A chap writing in uk.railway a few years back had this detailed explanation:
Quote ...The swing link is the 'pendulum' which supports the transverse bolster of the coach's secondary suspension from the bogie frame. In general there are four links, two on each side although some French designs used only two. On the BT10 bogie under the HST coaches the airbags at each end of the bolster support a transverse 'spring plank' into which the pivot pin of the coach is inserted. The spring plank is located by radius arms in the case of the BT10 to the bolster so there is no relative motion between the two except vertically and in roll. The swing links then permit the coach body to move sideways with respect to the bogie frame under control of the horizontal damper. The longer the swing links the lower the natural frequency of the 'pendulum'. This design was adopted as at the time there was no experience of using air bags as swing links. Sometime later the bogie under the Class 313 electric units used airbags which combined the vertical spring and horizontal flexibility functions and this has since become standard. In the initial HST design the swing links were as long as possible and the ends hung below the bolster. At each end of the swing links are longitudinal 'knife edges' to permit the link to swing with low friction on the bogie frame and bolster and which also transfer the body weight from the bolster (at the lower end of the link) to the bogie frame at the top of the link. To permit the suspension to be set up accurately these 'knife edges' could be adjusted by large nuts and lock nuts on screw threads cut into the ends of the link. The protruding threaded end at the bottom of the link could get quite close to the third rail in Southern territory under critical conditions of worn tyres, body roll and third rail positional tolerances. As a result to permit HSTs to operate on the Southern the swing link was modified to get the lower end away from the third rail by raising the lower knife edge and omitting (or shortening) the lower threaded portion. Although this allowed HSTs to run in third rail areas it meant that the coaches lost the silky lateral motion they had as new as the natural lateral resonance frequency was raised. Archived here: http://newsgroups.derkeiler.com/Archive/Uk/uk.railway/2009-06/msg00365.html What has also confused matters is that there are explanations online that misleadingly concentrate on the safety straps - the 'wire rope assemblies' shown in bnm's pictures on both the SSL and LSL bogies. Some LSL bogies have a steel 'stirrup' rather than a wire rope - this can be seen in the line drawing above, and from what I've seen this is also quite near the third rail. Indeed one online resource reads as though the wire rope and steel stirrup are the swing links, and they are the defining features of the two types - although it is now obvious that wire ropes are fitted to both SSL and LSL types, although I believe that the 'stirrups' are only present on some LSL bogies. The explanation above suggests that original LSL bogies have a better ride, though I wonder if it is noticeable to anyone other than an engineer. I expect BR's decision to only modify a certain proportion of the HST sets was financially driven. Paul Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: JayMac on April 10, 2015, 18:46:42 The only place I've seen a BT10 with a stirrup is on a Greater Anglia loco hauled Mk3.
Is it possible that many LSL bogies have been retro-fitted with the wire strap in place of the stirrup? Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: stuving on April 10, 2015, 19:02:14 Further confusion is caused by that quoted text, which says
Quote On the BT10 bogie under the HST coaches the airbags at each end of the bolster support a transverse 'spring plank' into which the pivot pin of the coach is inserted. The diagram (and other sources) have the swing links supporting the spring plank, on which rest the springs, and then the bolster, which bears the pivot. Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: paul7575 on April 10, 2015, 20:05:00 Further confusion is caused by that quoted text, which says Quote On the BT10 bogie under the HST coaches the airbags at each end of the bolster support a transverse 'spring plank' into which the pivot pin of the coach is inserted. The diagram (and other sources) have the swing links supporting the spring plank, on which rest the springs, and then the bolster, which bears the pivot. Agree. But I think the useful part of the text is the way the knife edge bearings and their adjustments are described. Paul Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: 4064ReadingAbbey on April 10, 2015, 20:49:09 Paul7755,
There is a slight difference in the lateral ride between the LSL and the SSL BT10 bogies. I first noticed it many years ago when I changed coaches (for reasons now long forgotten) and thought that the second one felt more 'nervous'. It turned out that the 'nervous' one had SSL bogies. As the ride also depends on the track quality it is difficult to tell the difference between the bogies without a direct comparison and with good quality track the difference is marginal. However in the latter days of BR the quality of the Western's track deteriorated and then it was quite easy to tell the difference between the bogies - now it is less so. There was one other bogie change which has had an effect - one of the first things after privatisation that Great Western Trains did was to start a campaign change for the radius arms (traction rods - item 8 in the drawing) which locate the bogie frame to the bolster as the rubber bushes had become worn. This removed the jerk which was noticeable at the start of braking and also improved the ride back towards the silky smoothness shown when the trains were new. To cut a long story short - the LSL bogies still give a slightly better lateral ride but on good quality track it is difficult to tell the difference. Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: Puffing Billy on April 11, 2015, 08:21:08 As Michael Jackson said, "Blame it on the bogie"
Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: 6 OF 2 redundant adjunct of unimatrix 01 on May 03, 2016, 12:40:57 I was given the reason for the nmt not visiting the southern main line as that is has LSL .... if that is the case does anyone notice a problem with two of its current diagrams
Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: paul7575 on May 03, 2016, 17:21:12 I was given the reason for the nmt not visiting the southern main line as that is has LSL .... if that is the case does anyone notice a problem with two of its current diagrams Wishful thinking by someone? ??? Not as regular a visitor here, (unlike the fast main lines such as ECML, WCML and GWML), but I've definitely seen it in the Southampton area often enough to realise that it definitely does visit these parts... Paul Title: Re: Long Swing Link/Short Swing Link HST Mk3 bogie differences Post by: PhilWakely on May 03, 2016, 17:40:59 I was given the reason for the nmt not visiting the southern main line as that is has LSL .... if that is the case does anyone notice a problem with two of its current diagrams The NMT runs an Old Oak Common to Salisbury (or Weymouth) via Reading, Basingstoke, Salisbury, Yeovil Junction and Exeter St Davids roughly every 5 weeks on a Thursday and it runs between Basingstoke and Worting Junction) over the third rail. This page is printed from the "Coffee Shop" forum at http://gwr.passenger.chat which is provided by a customer of Great Western Railway. Views expressed are those of the individual posters concerned. Visit www.gwr.com for the official Great Western Railway website. Please contact the administrators of this site if you feel that content provided contravenes our posting rules ( see http://railcustomer.info/1761 ). The forum is hosted by Well House Consultants - http://www.wellho.net |