philsandy Posted January 26, 2017 Share Posted January 26, 2017 Just out of curiosity, does anyone know of track work in any model gauge where curves and points have been made using straight lengths of rail only, as per the real thing, rather than flexing the rail to form a curve? Would this even be possible in a model, say 4mm or 7mm scale, and what would be the minimum radius that this could be achieved? Link to post Share on other sites More sharing options...
Fat Controller Posted January 26, 2017 Share Posted January 26, 2017 The only places I have seen curves formed of straight track are some industrial sites with very low maximum speeds. Rail may appear straight when it arrives on site, but it flexes just like its model counterpart, and so takes whatever curve is imposed on it, Link to post Share on other sites More sharing options...
Grovenor Posted January 26, 2017 Share Posted January 26, 2017 Just out of curiosity, does anyone know of track work in any model gauge where curves and points have been made using straight lengths of rail only, as per the real thing, rather than flexing the rail to form a curve? What real thing are you thinking of? Regards Link to post Share on other sites More sharing options...
gordon s Posted January 26, 2017 Share Posted January 26, 2017 Not sure I understand the question as all my turnouts are made from straight rail without curving. The only thing I would add is that bullhead rail is easier to curve than flat bottom. Link to post Share on other sites More sharing options...
Grovenor Posted January 26, 2017 Share Posted January 26, 2017 Not sure I understand the question as all my turnouts are made from straight rail without curving. The only thing I would add is that bullhead rail is easier to curve than flat bottom. Gordon, your answer is equally confusing, how would you know that bullhead is easier to curve if you have built your turnouts without curving? Whether model or 'real thing' the rails are mostly curved during laying, although with FB rail pre-curved may be used for tight curves, <100m radius say. Poorly laid sidings/industrial lines do sometimes show the 50p effect where the rail near the joints tries to straighten out. Hopefully Philsandy will clarify his question. Regards Link to post Share on other sites More sharing options...
Mike Storey Posted January 26, 2017 Share Posted January 26, 2017 What do you mean by "the real thing"? I can only think of narrow gauge situations where this applied, and then only in very short stretches. Link to post Share on other sites More sharing options...
Junctionmad Posted January 26, 2017 Share Posted January 26, 2017 Im not sure the OP quite understands the question he asked Link to post Share on other sites More sharing options...
28XX Posted January 26, 2017 Share Posted January 26, 2017 At the risk of pandering to a trollesque question, the compliance of rail in model scales does not correspond to the compliance of real rail on real railways. One only has to consider a CWR train, the rail lengths run continuously over several wagons. The train runs happily over curves and junctions. Do that on a model and the whole lot will derail at the first curve, even if it is scaled of a prototypical radius. Link to post Share on other sites More sharing options...
philsandy Posted January 26, 2017 Author Share Posted January 26, 2017 Gordon, your answer is equally confusing, how would you know that bullhead is easier to curve if you have built your turnouts without curving? Whether model or 'real thing' the rails are mostly curved during laying, although with FB rail pre-curved may be used for tight curves, <100m radius say. Poorly laid sidings/industrial lines do sometimes show the 50p effect where the rail near the joints tries to straighten out. Hopefully Philsandy will clarify his question. Regards "real thing" = Standard gauge, 4' 8.5" I must have misunderstood. I thought that bullhead rail came in straight 60 foot lengths, and to produce a curve, the first rail would be laid, and then each adjoining rail there after would deviate very slightly, to the left or the right, (depending which way the curve was to flow) and so on. So over several lengths of rail a gradual curve was produced, but made from many straight lengths of rail. Was bullhead rail flexed to form curves? Link to post Share on other sites More sharing options...
Junctionmad Posted January 26, 2017 Share Posted January 26, 2017 "real thing" = Standard gauge, 4' 8.5" I must have misunderstood. I thought that bullhead rail came in straight 60 foot lengths, and to produce a curve, the first rail would be laid, and then each adjoining rail there after would deviate very slightly, to the left or the right, (depending which way the curve was to flow) and so on. So over several lengths of rail a gradual curve was produced, but made from many straight lengths of rail. Was bullhead rail flexed to form curves? No each length was curved by the crew laying it . bullhead is actually very flexible Hence an interesting anecdote, when I was 11 we were building our 2nd house, my father needed an RSJ to carry the floor across a void , to " save money " he bought a 15 foot of Bullhead, because "everyone " said sure rail is really " strong". after the floor on top of it was put in , it adopted a lovely " catenary " . it was an expensive lesson in the flexibility of bullhead. Link to post Share on other sites More sharing options...
Grovenor Posted January 26, 2017 Share Posted January 26, 2017 No each length was curved by the crew laying it . bullhead is actually very flexible Same goes for flatbottom until the radius gets really tight, eg <100m. Regards Link to post Share on other sites More sharing options...
gordon s Posted January 26, 2017 Share Posted January 26, 2017 Gordon, your answer is equally confusing, how would you know that bullhead is easier to curve if you have built your turnouts without curving? Well firstly I've heard that from many model track builders over the years and the sheer mechanics of the T section of a flat bottom rail must mean it is stiffer that an bullhead section rail. Of course, I lay the curved track in turnouts from straight rail. I meant I didn't pre bend it to shape. Link to post Share on other sites More sharing options...
Mike Storey Posted January 27, 2017 Share Posted January 27, 2017 In narrow gauge construction, I played a part as a volunteer on the Ffestiniog Deviation in my yoof, and in later years on the Corris. The track used is FB and tends to be in very short sections, 20' - 30' (as opposed to the more normal 60' on standard), which is the most that a small track gang can manage - we did not have the luxury of dozens of peeps for each job. On the Ffestiniog, rail was pre-bent, as they had chaps with the skills and equipment to do it, but on the Corris, where normally only perhaps four or five of us would turn up for a weekend p/way job, we laid each section as it fell. A very well qualified guy from Aberystwyth Uni would then direct us as to how he wanted it fixed down, which after a day's work would magically produce a "curve". He and another guy practically run the whole thing, and without them, it would have died long ago, or cost a fortune to be done professionally. We/they created the whole new layout at the new carriage shed and refurbished loco shed and new works shed in this way over many weekends, with just professional (paid) help for the inspection pit. In summary, the track went down as "straights" but adopted a curve on spiking, stressing and packing, just like Peco.... Link to post Share on other sites More sharing options...
Grovenor Posted January 27, 2017 Share Posted January 27, 2017 Well firstly I've heard that from many model track builders over the years and the sheer mechanics of the T section of a flat bottom rail must mean it is stiffer that an bullhead section rail. Stiffer, of course, but not so stiff it becomes a problem, even with bullhead it helps to pre-curve it a bit between the fingers if building to a small radius, removes the stress from the fixings while you glue or solder. But as noted above model rail is relatively much stiffer than full size rail, as mentioned train loads of long welded FB will happily bend through the curves on the track. Regards Link to post Share on other sites More sharing options...
gordon s Posted January 27, 2017 Share Posted January 27, 2017 The only thing I would add is that bullhead rail is easier to curve than flat bottom. ......the sheer mechanics of the T section of a flat bottom rail must mean it is stiffer that an bullhead section rail. Stiffer, of course, but not so stiff it becomes a problem, even with bullhead it helps to pre-curve it a bit between the fingers if building to a small radius, removes the stress from the fixings while you glue or solder. But as noted above model rail is relatively much stiffer than full size rail, as mentioned train loads of long welded FB will happily bend through the curves on the track. Regards I didn't say it was a problem, just that it was stiffer...... Link to post Share on other sites More sharing options...
RMweb Gold Rowsley17D Posted February 8, 2017 RMweb Gold Share Posted February 8, 2017 Pre-bending rail for turnouts is a must when using C&L chairs and ply sleepers as unlike rail soldered to copper-clad the rail on a curve will move in the chairs and try to straighten out again. Link to post Share on other sites More sharing options...
RMweb Premium Siberian Snooper Posted February 8, 2017 RMweb Premium Share Posted February 8, 2017 I have laid code 82 flat bottom 6B turnouts using Peco F/B bases and slide bases on ply timbers without pre bending anything except the knuckles on the wing rails, as per the full size railway. Link to post Share on other sites More sharing options...
ozzyo Posted February 9, 2017 Share Posted February 9, 2017 No each length was curved by the crew laying it . bullhead is actually very flexible Hence an interesting anecdote, when I was 11 we were building our 2nd house, my father needed an RSJ to carry the floor across a void , to " save money " he bought a 15 foot of Bullhead, because "everyone " said sure rail is really " strong". after the floor on top of it was put in , it adopted a lovely " catenary " . it was an expensive lesson in the flexibility of bullhead. All rail is strong in the right section, if your dad laid the rail with the H section as the H up right this is the lowest strength point, but if the rail is used as an I beam I would have doubt that it would have bent. I remember an old large shop (some would call it a small superstore) in Barrow that used tram rail to support some of the floors, this is not a story that I've been told as I have seen it. The rail was base to the top and the running face with the flange-way facing down. The store was the Coop. that has now turned in to the Furness Railway Pub and hotel, if you can see any of the rail now I don't know. You would have to spend a night or two in the place to find out. OzzyO. Link to post Share on other sites More sharing options...
F-UnitMad Posted February 9, 2017 Share Posted February 9, 2017 ... as noted above model rail is relatively much stiffer than full size rail, ... As demonstrated at Dawlish a few years ago. I don't think Peco flextrack dances about like this even if you do just hold it out at either end Link to post Share on other sites More sharing options...
Mike Storey Posted February 9, 2017 Share Posted February 9, 2017 As demonstrated at Dawlish a few years ago. I don't think Peco flextrack dances about like this even if you do just hold it out at either end They must have cut through the plastic web before they laid it - silly billies! Link to post Share on other sites More sharing options...
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