Adjusting a parallel track (as apposed to strict curve) may be constructed from any set of existing sectional curves by adding a pair of short straights at each end , with the short tracks being of different length. using this as a base 30 degree building block you can then work up in multiples to ... 60, 90 ... degree.

A similar process could be used for 15 degree pairs, however these do not exist for R4,R5 (Which I take in context to be the 2241 and 2251 items)

using the standard available lengths a
... 2202/2293 pair with their 3.7mm difference would produce a 50.79 spacing of track (Outer effective radius for 90 degrees = 772.63)
... 2203/2208 pair with their 5.1mm difference would produce a 45.57 spacing of track (Outer effective radius for 90 degrees = 730.46)
... 2208/2293 pair with their 6.2mm difference would produce a 41.46 spacing of track (Outer effective radius for 90 degrees = 749.49)
... 2203/2204 pair with their 7.5mm difference would produce a 36.61 spacing of track (Outer effective radius for 90 degrees = 702.47 (or see below 681.98))
... 2202/2208 pair with their 9.9mm difference would produce a 27.65 spacing of track (NOTE: * track ties overlap)
... 2203/2293 pair with their 11.3mm

If you cut the straights yourself then the only thing to worry about is that the difference does not cause roadbed overlap
As is the case with the 9.9mm difference of 35.1(2208)/45(2202)




The 2203/2204 pair has a convenient 7.5 mm difference, so instead of butting 2 of these pairs together (which gives a 15mm difference) you could just use a single 2202/2203 pair
Note: the 2202/2293 delta (3.7) is very close to half the 2203/2204 (7.5) delta and will work using this technique

Edited by user 01 April 2016 03:46:46(UTC)  | Reason: Not specified

Opening comment on tollerence ...
for "so called" 57mm track spacing as prohuced by the 2272,2273,2274 items
Curveature : Using the provided specs of 902.4mm radius and an arc if 14dgrees26minutes the spacing is actually 56.96
Straight Length : The Marklin publications also imply a matching length for the straight (documented at 225mm) can be made up with a 2200(180mm) + 2293(41.3mm). These actually sum to 221.3 which is a whopping 3.7mm out.

Your mileage may vary ...


A 57mm track spacing would be made to work with approx 2.5mm(2.55) - while there is no single base set/pair to help with this for the lead-in to the curve, the x2 interim delta of 5.1mm can be achieved with a 2203/2208 pair.

The 2.55mm delta is almost lost in the rounding,
You may wish to simple shave this off the (Outer) lead-in track rails with a Dremel, or leave a gap (Inner track) and fill with solder if really needed

Edited by user 02 April 2016 23:58:15(UTC)  | Reason: Not specified

exactly: the best technically but not aesthetic and I've tried it once and looks shocking with long passenger carriages the way they move side to side

I think one has to realize there are ways of doing it and there are ways of avoiding certain perfections but theoretically still maintaining a 57mm distance between tracks
I couldn't see with the track plan where the problem was or is implementing some common and mathematical measurements to achieve the 57mm distance and there is always the perfect solution to use the flexi track on the inside or outside.

I've tried once by cutting a curved track (C-track sleek turnout) in half and created a slim s-curve to be able to connect tracks from opposite sides with a difference distance and it looked shocking aesthetically when a loco with its carriages went past it , in the end I could bare it any longer and cut away some of the cork bedding and just bent the track over a length of about 2 meters and now you wouldn't know it had a different distance in the beginning and there is no visual discrepancy you would notice.

Sometimes you just have to bend the rules



John