sir douglas Posted August 15, 2014 Share Posted August 15, 2014 hi, I already know why 9F's have been banned on the mainline, because of raised check rails, but something that i would now like to know is, Why are the check rails raised?, and something mentioned on the nat-pres forum, why havent there been any tests or experiments to see how check rails actually effect 9F's? instead of just being (maybe) over cautious, but "better safe than sorry" is always the a good thing. in this day & age we have computer softwares that can perfectly model the ride of a 9F over a raised check rail so "no 9F was harmed in the making of this" Regards, Sam. Link to post Share on other sites More sharing options...
RMweb Premium jamie92208 Posted August 15, 2014 RMweb Premium Share Posted August 15, 2014 I suspect that it is due to the potential overthrow that would bring the flangeless centre driver over the raised part of the check rail. IIRC there was a problem with I think Evening Star when it encountered a raised checkrail for the first time. Jamie Link to post Share on other sites More sharing options...
sir douglas Posted August 15, 2014 Author Share Posted August 15, 2014 i understand that, but why are check rails raised? Link to post Share on other sites More sharing options...
Poor Old Bruce Posted August 16, 2014 Share Posted August 16, 2014 I think it may be more to do with getting two section of flat-bottom rail close enough together to create the flangeway without machining too much rail away to be able to do the job effectively. Link to post Share on other sites More sharing options...
Boris Posted August 16, 2014 Share Posted August 16, 2014 I think it may be more to do with getting two section of flat-bottom rail close enough together to create the flangeway without machining too much rail away to be able to do the job effectively. I don't recall ever seeing a flat bottom checkrail, but then again its not something I really look at. Looking at some point photos the lower flange appears to be missing on one side in the relevant places though. This is what they seem to do there days, not so much a rail as what appears to be U or box section steel. The best explanation I have seen of the function of check rails as well as some technical data in laymans terms is in the RAIB report into that 47 that derailed and caught fire in Manchester, it is definitely worth a look. Link to post Share on other sites More sharing options...
roythebus Posted August 17, 2014 Share Posted August 17, 2014 I think you''ll find the raised check rail that can cause trouble is on the K crossing on diamond crossings and double slips. This is a casting on modern pointwork. I haven't seen raised check rails on plain pointwork in the UK, but then I haven't really been looking as I don't go by train very often. Link to post Share on other sites More sharing options...
Dave Scott Posted August 17, 2014 Share Posted August 17, 2014 I think you''ll find the raised check rail that can cause trouble is on the K crossing on diamond crossings and double slips. This is a casting on modern pointwork. I haven't seen raised check rails on plain pointwork in the UK, but then I haven't really been looking as I don't go by train very often.I agree it is the cast crossing in the centre of a diamond. I bet most modelers have had a vehicle decide to change tracks on a diamond rather than go straight. The big railway has similar potential problems but tighter tollerances usually keep things OK. I assume the raised lip gives greater guidance when using smaller wheels. Some container waggons use wheels more suited to a roller scate to achieve a low profile for transporting the bigger boxes Link to post Share on other sites More sharing options...
PenrithBeacon Posted August 17, 2014 Share Posted August 17, 2014 I wonder what would happen if a flanged tyre was added to the currently flangeless wheel? Certainly the loco would be restricted in the radii it could run on (the weight diagram shows 4.5 chains 'dead slow' for a standard 9F), but what radii would a fully flanged 9F be able to negotiate? Anyone have the maths? Regards Link to post Share on other sites More sharing options...
RMweb Premium jamie92208 Posted August 17, 2014 RMweb Premium Share Posted August 17, 2014 IIRC the 2nd and 4th drivers also have reduced flanges so it might not be as simple as that. Jamie Link to post Share on other sites More sharing options...
RMweb Gold unravelled Posted August 17, 2014 RMweb Gold Share Posted August 17, 2014 Isn't there an unrestored 9f? Perhaps time to create the standard 2-8-2... Dave Link to post Share on other sites More sharing options...
Edwin_m Posted August 17, 2014 Share Posted August 17, 2014 Manchester Metrolink has raised checkrails on all pointwork and I believe it is still intended that the same will apply on sections shared by the tram-train in Rotherham. This is because (simplifying somewhat) railway flanges are too big to run on tramway street track, so tram wheels have a thinner flange so their back-to-back is too large to be compatible with railway switches and crossings. Hence the Metrolink and tram-train wheels increase to the heavy rail thickness above top of rail and this part can engage with a raised check rail. It is interesting to note that raised checkrails are standard on the Continent including routes used by preserved 2-10-0s with flangless centre drivers. Link to post Share on other sites More sharing options...
Horsetan Posted August 19, 2014 Share Posted August 19, 2014 ... raised checkrails are standard on the Continent including routes used by preserved 2-10-0s with flangless centre drivers. The various German Br.44, 50 and 52 2-10-0s appear to have flanged centre drivers. Link to post Share on other sites More sharing options...
Edwin_m Posted August 19, 2014 Share Posted August 19, 2014 I believe there is at least one type that has flangeless, as I queried it with some contacts in Germany when this came up a few years ago on a vaguely related project. However I don't think I have any details any more. Link to post Share on other sites More sharing options...
LNERGE Posted August 19, 2014 Share Posted August 19, 2014 I think you''ll find the raised check rail that can cause trouble is on the K crossing on diamond crossings and double slips. This is a casting on modern pointwork. I haven't seen raised check rails on plain pointwork in the UK, but then I haven't really been looking as I don't go by train very often. I agree it is the cast crossing in the centre of a diamond. I bet most modelers have had a vehicle decide to change tracks on a diamond rather than go straight. The big railway has similar potential problems but tighter tollerances usually keep things OK. I assume the raised lip gives greater guidance when using smaller wheels. Some container waggons use wheels more suited to a roller scate to achieve a low profile for transporting the bigger boxes Here's an obtuse crossing with raised check rail right where you don't want it... Hellifield.. Link to post Share on other sites More sharing options...
tamperman36 Posted April 10, 2015 Share Posted April 10, 2015 Could it be that Network Rail have put the restriction in place as they are worried that the castings could be damaged as the flangless wheel set rides over it, thus costing THEM MONEY. Link to post Share on other sites More sharing options...
RMweb Premium phil-b259 Posted April 10, 2015 RMweb Premium Share Posted April 10, 2015 Could it be that Network Rail have put the restriction in place as they are worried that the castings could be damaged as the flangless wheel set rides over it, thus costing THEM MONEY. UTTER RUBBISH! It is a FACT that if you try and run a flangless wheel over such castings there IS A VERY GOOD CHANCE IT WILL DERAIL - possibly with catastrophic results. Would you want to be the one standing up in court saying to a judge "well even though we know it a derailment risk we decided to ignore it to keep steam enthusiasts happy", particularly if said derailment end up causing serious injury or death. What most mainline steam enthusiasts seem to forget is NR is there to provide a transportation service for todays passengers and freight - not pander to the needs of steam enthusiasts, whose trains are underwritten by NR anyway (in the sense that the delay minutes NR can pass on to charter operators are capped with NR having to make up the difference, which could be considerable thanks to how full MOST sections of our railway network has become). Also what may or may not happen in Germany is IRRELEVANT - DB don't run, or specify the trackwork over here, NR do and as such we have to go with what they say. Now while I don't want to see steam banned from the national network, it has to fit within the constraints of the modern system as far as I am concerned. Therefore if NR says no to flangeless wheels, for sound engineering reasons then that should be the end of it. Link to post Share on other sites More sharing options...
LNERGE Posted April 10, 2015 Share Posted April 10, 2015 The ban on 9F's on lines with raised check rails is not new. The rule came in very soon after they were introduced. Some earlier bullhead points had raised check rails. There were less of them once the 9F's started to appear. I have a document lurking somewhere listing lines they were allowed to use on the GNGE. Basically main running lines and loops, to and from shed by approved route and 'NOT IN SIDINGS AND LINES EQUIPPED WITH RAISED CHECK RAILS' Any heritage line that entertains the use of these magnificent machines has to look closely at their own permanent way. Check rails do not wear down compared to running rails. A stock rail worn to near scrapping size can be alarmingly lower than the check rail which is the same as having raised check rails. More than one heritage railway has found this out the hard way... Link to post Share on other sites More sharing options...
Andy Y Posted October 25, 2015 Share Posted October 25, 2015 Thanks to LNERGE for the specific information supplied in this scan: Link to post Share on other sites More sharing options...
LNERGE Posted October 25, 2015 Share Posted October 25, 2015 "Certain engines in classes 2P, 4P and 4F marked * are not within gauge, by reason of extreme height, and are indicated by blue discs on the cab sides" Has anyone a photo of a loco so adorned? Link to post Share on other sites More sharing options...
LNERGE Posted October 25, 2015 Share Posted October 25, 2015 Damn i was always hoping a picture of a CoBo would turn up at Rectory Junction or Netherfield.. <g> Link to post Share on other sites More sharing options...
Sheffield Posted October 26, 2015 Share Posted October 26, 2015 Interesting that the notice bans 9fs from pick up goods. Leicester Shed had no problem using them on the daily pick up duty that visited various goods yards along the South Leicestershire line and up the Enderby branch . It had been a 3F or 4F job, but towards the end of steam anything could turn up, including Jubilees and Royal Scots. 9Fs were not at all uncommon. Link to post Share on other sites More sharing options...
IWCR Posted October 27, 2015 Share Posted October 27, 2015 These days a 9f would not need to access tightly curved lines when out on the main line. It ought to be possible to fit a flanged tyre to the centre drivers to permit its use. Coupled wheelbase 21' 8" (for comparison a P2 is 19' 6") Of course it would need a detailed study to ascertain what curves it could handle and what tyre profiles would be acceptable for the wheelsets. The power available would be extremely good but wheel diameter would limit permitted speed for the mainline which is less desirable for practical use. Link to post Share on other sites More sharing options...
pete_mcfarlane Posted October 27, 2015 Share Posted October 27, 2015 The power available would be extremely good but wheel diameter would limit permitted speed for the mainline which is less desirable for practical use. I'm not sure if speed would be an issue, given that steam is now limited to 75mph and there are plenty of instances of 9Fs going faster than that . One of Grantham's 9Fs was supposedly timed at nearly a hundred whilst substituting for a failed Pacific. Link to post Share on other sites More sharing options...
LMS2968 Posted October 27, 2015 Share Posted October 27, 2015 Speed would definitely be an issue. Under current regulations, a 9Fs five foot diameter wheels would limit it to, I believe, 50 mph. which gives pathing issues over many lines where only gentle curves are to be encountered. Former exploits in BR days have nothing to do with it. Link to post Share on other sites More sharing options...
pete_mcfarlane Posted October 27, 2015 Share Posted October 27, 2015 Ah, I'd not twigged that fact. Link to post Share on other sites More sharing options...
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