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teaky

Do I need a transition curve?

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Hmm, if you are using 3 link then you are really going to be pushing stock backwards buffer to buffer. Ok, I model a tight version of EM, but pushing 20 hefty wagons backwards from curves into pointwork without problems will take a fair amount of work to get right. Coaches pushed backwards buffer to buffer can be an issue, sideplay becomes an issue and a lot depends on how much off centre the wheels and track allow the stock to be . 

 

To answer your original question, the answer is yes, use a transition to ease out of a fixed radius curve into a section that it straight or of a lesser radius. What you don't want is a vehicle with buffers offset to the left since its on a curve locking with a vehicle with buffers on the centre since its on a straight, or worse buffers on the right since its on a reverse curve. ( or the other way round ) 

 

Some tricks for real buffer to buffer work. Spring the buffers, really try it.  File off any little pip on metal buffers where they were parted off, they can catch and cause issues.  Oil them, at a curve the buffers slide over each other, sounds daft but it does make a difference, which is why real railways did it. 

 

One dirty trick, go up a buffer size for coaches if they do cause trouble. 

 

Anyway, at 1 min in there is a train going back, off a curve into pointwork and across a long crossing. My tracklaying is not perfect, you can see the compensation working and the buffers bouncing a bit. 

 

 

 

 

 

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6 hours ago, Dave John said:

Hmm ...

 

Thanks Dave.

 

... from curves into pointwork ... - In this particular instance I am only dealing with a curve into a straight and no points.

 

... will take a fair amount of work to get right ... - That was what prompted me to start this thread.  Perhaps I had better not try to short cut things and I should set up a test length of track and as many wagons as I can find.  I was trying to avoid unpacking stock because it will all have to go away again before I continue with the baseboard build.

 

... Coaches pushed backwards buffer to buffer can be an issue ... - I am less concerned about coaches because I think the type of coupling I intend to adopt will help avoid buffer lock.  Plus it is easier to use larger buffer heads or to hide things like horizontal bars without it being too obvious.

 

... sideplay becomes an issue and a lot depends on how much off centre the wheels and track allow the stock to be ... - Although I'm using 00 gauge, I shall aim to standardise back-to-backs and clearances in the hope of mitigating this as much as I can.

 

... yes, use a transition ... - I think I have already concluded that avoiding a transition curve may be too risky.  Even where responses have not quite answered the question in the original post, it is clear that transition curves are strongly favoured.

 

... Some tricks ...

     ... Spring the buffers - One of my aims.  I already have a number of converted wagons and will aim for as high a proportion as I can.

     ... File off any little pip on metal buffers - I will look closely at all buffers as wagons are fettled.

     ... Oil them - That's a good idea.  It had occurred to me to oil the buffer shafts and springs but not the faces.

     ... go up a buffer size for coaches if they do cause trouble. - That one I had thought of.  Ditto for longer wheelbase goods wagons.

 

 

Anyway, at 1 min in there is a train going back, off a curve into pointwork and across a long crossing. My tracklaying is not perfect, you can see the compensation working and the buffers bouncing a bit. - A lovely layout and an enjoyable video.  Thank you.

 

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19 hours ago, Dave John said:

 

 

 

 

 

 

Apologies for the thread hijack.

 

A lovely bit of work there.  Something that caught my eye towards the end was the working Scotch Derrick.  Do you have any details on that ?

 

Thanks

 

Adrian

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image.png.39ffb54b94ee57118f032278b2bd8dbc.png

  

Bit like the curve 'line' they use on Motorway exits if a curve is required at the latter part of the exit at, say, a roundabout, Very subtle and you hardly notice until you really look. The early section of the exit is almost straight and then the curve is introduced; bit like a Lawn Bowl's bias line with the tight curve towards the end of the run.

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Right then.  I am now convinced that any attempt at doing without a transition curve at the entrance to the bit of storage I was concerned about is a daft idea and I am asking for trouble.

 

I have been playing around with AnyRail for the last few days to see if I could come up something that fitted and yesterday I thought I'd cracked it.  I then drew out a track base on a sheet of plywood.  This morning I cut the track base out and tried it for size.  I haven't actually cut the lead in curve I was so concerned about but since the plywood takes up fractionally less space, I am confident it will fit.

 

Thank you all for your contributions to this thread and for helping to resolve this little matter.  :good_mini:

 

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