RBE Posted April 7, 2011 Share Posted April 7, 2011 Pretty much as the title says really. How do crossovers work on super elevated track? The frogs of each of the points will surely be on different levels. I ask as I have an idea for a layout that i want to introduce a cant to the track but will need a crossover in the canted track for the plan to work. Cheers Cav Link to post Share on other sites More sharing options...
RMweb Premium Chris116 Posted April 7, 2011 RMweb Premium Share Posted April 7, 2011 The simple answer is that on the real railway they would not put points in an area of canted track. Services in the Bridgend area are the way they are because of this! Chris Link to post Share on other sites More sharing options...
Edwin_m Posted April 7, 2011 Share Posted April 7, 2011 They put S&C on a curve if they have to - Sheet Stores Junction near Trent has a canted double junction with a 10mph restriction over the "negative cant" on the diverging route. But maintenance is difficult and they would not be put in where there is any alternative. Link to post Share on other sites More sharing options...
RMweb Gold martin_wynne Posted April 7, 2011 RMweb Gold Share Posted April 7, 2011 Pretty much as the title says really. How do crossovers work on super elevated track? Hi Cav, See: http://85a.co.uk/forum/view_topic.php?id=150&forum_id=1#p761 More discussion and detailed notes for two-level chairs: http://groups.yahoo.com/group/templot/message/4693 The report on the Grayrigg accident ( http://www.raib.gov.uk/cms_resources.cfm?file=/071003_IR022007_Grayrigg.pdf ) gives the design cant at that location as 95mm, and includes a photo of the crossover (Figure 8) which shows a single plane across both tracks, with the outer track higher than the inner track. regards, Martin. Link to post Share on other sites More sharing options...
RBE Posted April 7, 2011 Author Share Posted April 7, 2011 Well the flat plane idea with advetse cant makes sense. Thats what i imagined but didnt know if that was the case in reality. How well does that kind of thing work in model form? I really want a cant as the layout i have in mind is wcml based but on a constant 4ft radius so in order for it to look at all real i have to cant the track! Link to post Share on other sites More sharing options...
Southernman46 Posted April 7, 2011 Share Posted April 7, 2011 Well the flat plane idea with advetse cant makes sense. Thats what i imagined but didnt know if that was the case in reality. How well does that kind of thing work in model form? I really want a cant as the layout i have in mind is wcml based but on a constant 4ft radius so in order for it to look at all real i have to cant the track! Firstly, no Track Engineer in his right mind would put a crossover on a curve let alone as canted curve - however in the real world there are many examples where space and geography mean that this has to be done. As per the real thing, if the crossover has to go on a canted curve and a normal 6ft spacing between adjacent tracks has to be maintained then the cant must be uniform across the track to ensure that the crossover track does not have adverse cant. Don't cant the tracks individually as you would normally do on a section of plain line. So, for example, if the lowest rail (inside rail of curve) is at 0 then the highest rail of the four (outside rail of curve) will be say 10mm higher. The crossover track will then naturally pass from high to low track without too much adverse cant. Using the longest points possible will also help the problem. Link to post Share on other sites More sharing options...
great central Posted April 7, 2011 Share Posted April 7, 2011 298 posted a picture (or link to) some time ago showing the effects of the canted crossover at the south end of Carstairs Junction. Rakes of mk4 stock are taken through there several times a day. On the model it has been flattened out quite dramatically, but is still quite impressive to see a train snaking through. As Edwinm says above Sheet Stores Junction is a bit of a bind, 10mph over it and it still feels ropey, much better since it was relaid a couple of years ago though. Before you'd swear that couplings weren't designed to displace that much! Edit: Found the link to the picyure of Carstairs part way down the page: http://www.jhowie.force9.co.uk/carstairs.htm Link to post Share on other sites More sharing options...
RMweb Premium jamie92208 Posted April 7, 2011 RMweb Premium Share Posted April 7, 2011 There was an accident report a couple of years ago about an MGR wagon derailing on one of the curves on one of the Tyne bridges (IIRC the western one) that involved a crossover on canted track and the derailment occurred because the suspension of the MGR waqgin hadn't been properly set up and couldn't cope with the extra cant. There were severl comments baout the difficulty of the design but as mentioned above the crossover had to be in that place so it was put there but it wasn't ideal. Jamie Link to post Share on other sites More sharing options...
Glorious NSE Posted April 7, 2011 Share Posted April 7, 2011 As per the real thing, if the crossover has to go on a canted curve and a normal 6ft spacing between adjacent tracks has to be maintained then the cant must be uniform across the track to ensure that the crossover track does not have adverse cant. Don't cant the tracks individually as you would normally do on a section of plain line. An example to support that - this is Lostwithiel, both main running lines are canted on the same plane so the crossover is included in the cant instead of working against it. http://ukrailwaypics.smugmug.com/SwinginHotSpots-1/Cornwall/Lostwithiel/16299689_mEynf#1233108733_pfWSi-A-LB Even there the goods loops (which the train is headed out of) don't appear to have cant (or such noticeable cant anyhow) so it's moving from level to canted track as it joins the main in the background. Something like being in close proximity to a bridge might make such a solution impossible though... I'm sure i've seen a location that very much didn't fit that model though....I just can't recall where.... Link to post Share on other sites More sharing options...
ozzyo Posted April 7, 2011 Share Posted April 7, 2011 Hello All, Morecambe south junction used to be a double junction on a R/H curve with a switched common crossing. The main line speed was IIRC 75mph. Coming from Morecambe on to the up line was like being on a big dipper. The junction was rebuilt about 15-20 years ago, and is now a ladder junction with the crossover on the transition curve or just before it. The remodeling of the junction has increased the line speed to about 95mph IIRC. OzzyO. Link to post Share on other sites More sharing options...
RBE Posted April 7, 2011 Author Share Posted April 7, 2011 Well i might have a go at buiding a flat plane crossover then. Do you think i should cant the loop that the crossover leads to too or run the crossover over the outer track and flatten it out in the loop. If i maintain the cant i will end up with some serious height to the outer rail of the loop!! Link to post Share on other sites More sharing options...
coachmann Posted April 7, 2011 Share Posted April 7, 2011 It looks like crossovers were routinely put where they were required in steam days regardless of other considerations. I spend weeks messing around with the super-elevation problem at crossovers and a double junction just because the station I was laid out on a continuous curve. Railway engineers had cleverer ways of doing things than us mere mortals. For a start their points were designed to order. These two photo show some of the difficulties. The top photo shows the track where some super-elevation had been done using cardboard..... On sharper curves cork strips were used under the outer rail but I messed around for ages with the points. Eight or so of the Peco 5ft radius straight points had been curved to make this formation. Link to post Share on other sites More sharing options...
coachmann Posted April 7, 2011 Share Posted April 7, 2011 I have just dug up this further picture showing a more completed station with the crossover on the curve just visible behind the engine. The track & point on which the engine is standing were superelevated but I could not do this with the outer point as it affected the double junction seen in the top picture above, which had to be flat. Link to post Share on other sites More sharing options...
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