Superelevation

Discussion in 'RTR Trackwork' started by Dave C, May 20, 2017.

  1. Dave C

    Dave C Full Member

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    Having some reasonably large curves on Setforth Junction (36" plus) I rather fancied trying superelevation. My local model shop suggested it might cause running difficulties, but there seemed to be plenty of people doing it on You Tube, and having not permanently fixed and track down why not give it a go?

    How to do it? Lots of ideas, but all seemed to be remarkably long winded involving strips of plastic trying to spring back into a straight length, squashing plastic straws or filling / sanding. Why not just shim the track every 4 or 5 inches with a bit of cardboard I thought.

    So, cereal packet, scissors and glue stick in hand I made 3 thicknesses of shims approx 4 cm long and 5mm wide - 1, 2 and 3 layers. I eased the track pins out, and then started shimming the track on the outer side, a couple of single layers, then a couple of 2 layers and then the 3 Layer ones. I then gently tapped the track pins in and secured the track - not tightly as that could have deformed the sleeper or line of the track.

    I then checked that trains would run successfully which they did all bar one - which was in fact the best running loco we had on 'flat' track. Something wasn't right, and a quick wiggle of the loco on the track soon highlighted that it needed the pick ups cleaning - the camber was taking pressure off one side of the axles causing poor connections.

    The track was left like this for a few weeks just in case another problem reared its head, but none did. The track was then ballasted which gave it full support along the full length of the curve (just like the real thing).

    The difference it makes to the appearance of the trains as they run round the curve is marvellous :thumbup:
    [​IMG]

    It looks better with a video (albeit of poor quality) which also shows the shims - https://youtu.be/_iLSDwln0wY
     
  2. Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    I'll look forward to the video. The track looks good as does the whole scene.:thumbs:
     
  3. Dave C

    Dave C Full Member

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    Video uploaded - have edited orginal post with the link. drc
     
  4. Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    Smooth as you like. Looks very authentic.

    Toto
     
  5. Kimbo

    Kimbo Staff Member Moderator

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    Hi Dave, this is some thing I've been looking at doing with the final board on my extension, so great timing in posting it up.:thumbs: I've got some strips of wood ranging from 0.5mm to 2.0mm thick to use. Not sure yet if 2mm will be enough in o gauge, will try it and post up results.
    Kim
     
  6. gormo

    gormo Staff Member Administrator

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    G`day Dave,

    Good on you for having a go at the Super Elevation.

    I have never thought it was hard but some folks are intimidated by it.

    I had a crack at it many years ago on a large curving viaduct. Fortunately the track had not been laid yet. I used masking tape built up in layers of ever decreasing length over a distance of about four feet.??. It worked faultlessly because it was such a gradual change, but the trains looked good getting a bit of lean on when going through the curve....:thumbs:

    http://www.click:tophat:Gormo
     
  7. paul_l

    paul_l Staff Member Administrator

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    Spot on Dave - I would have done it the same-ish way, possibly with plasitcard, but cardboard certainly has worked well :thumbup:

    Paul
     
  8. Gary

    Gary Wants more time for modelling.... Staff Member Administrator

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    Great video Dave. :thumbs::thumbs:

    With a little research I found that the common height for superelevation in the 12":1' model is 6". This would equate to 2mm in OO gauge and 3.5mm in O gauge. I recall reading abut an exhibition layout, Broadford which had scale superelevation and back then in the late 80's early 90's, it did make a huge difference to the way the trains looked as they came hurtling around the curves.

    One thing to note on superelevation is the radius of the track to be lifted. In my opinion, I probably wouldn't incorporate superelevation on 1st, 2nd and 3rd radius set track. Generally anything say from 28" radii up would be ideal, but you may possibly introduce it on 4th radius set track. ;)

    Cheers, Gary.
     
  9. Dave C

    Dave C Full Member

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    Yes - I reckon 3 layers of cereal packet = about 2mm. When you look at it close up it doesn’t show that well unless you are looking round the curve, but when you are 4 or 5 feet away it does make a difference - not overdoing it is key.

    I live very close to the Queensville curve @ Stafford on the WCML - I suspect that is a bit more than 6" but suspect if I go out with a tape measure and spirit level I may get into serious trouble.

    http://www.trainspots.co.uk/locpage.php?ts_number=403

    And having now checked the Interweb I’ve found some USA information from CSX that indicates maximum permitted superelevation of 5”, and for the techies a chart showing radius / speed / elevation. However, 3 layers of cereal packet does it for me.:)
     
  10. Dave C

    Dave C Full Member

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    Just a quick update. Given how many loco's we have available on Setforth Junction it was a while before one loco was used, and it stalled terribly on the curve. It was one if not the best runner we had on the layout ( Hornby Fowler 2-6-4).
    Investigation revealed that as the loco went round the curve the wheels were sliding to one side of the chassis causing the pick ups to lose contact with the wheels. Didn't happen on the 'flat' curve at the other end of the layout (all visible running curves on SJ are minimum 36" radius).
    Given the loco had never been serviced it provided the impetus to do so. So if trying superelevation I would recommend getting the whole fleet to run round it before ballasting, and clean up all electrical contacts if stalling occurs before worrying about whether it's the superelevation.
    Dave C
     
  11. Gary

    Gary Wants more time for modelling.... Staff Member Administrator

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    Good tip there Dave. :thumbs:

    Cheers, Gary.
     
  12. Dave C

    Dave C Full Member

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    Further bit of engineering input. Just been stationary on a banked curve about 3 miles outside of Bristol Temple Meads in non tilting coaching stock - the spirit level app on my phone has recorded a 7 to 8 degree track camber ( and I have calibrated the table the phone is lying on!).
     
    Last edited: Apr 30, 2018
  13. Dr Tony

    Dr Tony Full Member

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    Nothing like some real world data to help with modelling:thumbs:
    You could also be really keen and use Google Earth imagery to measure the curve radius!
    For my first layout I calculated what super-elevation I needed, had to go back to my first year notes from surveying for that. An then found some rhine-stones placed strategically did the job well, the pack came with different sizes and they fitted nicely under the sleepers. Styrene strips would work well as you can then build the super-elevation up as the curve starts from the straight with a transition curve with easily calculable heights.
    From what I've noticed it was generally always NSWGR practice to have a much lower value of super-elevation than what was normally calculated, which is a good thing if you are on a slow train.
    Cheers
    Tony
     
    Last edited: Apr 30, 2018

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