Standard Railway Modelling Dimmensions

The following diagrams show the structure dimensions with the table indicating the appropriate measurements in various scales as devised by the British Railway Modeling Standards Bureau (BRMSB). 

Platforms, Station Buildings and Bridges dimensions

Platforms, Station Buildings and Bridges dimensions

Tunnel and Overbridge dimensions

Tunnel and Overbridge dimensions
Standard Dimensions

RefLetter See Note Prototype(Ft) N gauge(1/148) 2mmFine scale TT3(3mm) HO(3.5mm) OO(4mm) EM(4mm) O fine(7mm)
A 1 08.00 16.50 16.00 24.00 28.00 32.00 32.00 56.00
B 1 06.25 12.89 12.50 18.75 21.75 25.00 25.00 43.75
C 1 12.50 25.78 25.00 36.75 43.75 50.00 50.00 87.50
D 2 03.00 06.18 06.00 09.00 11.50 12.00 12.00 21.00
E 10.50 21.65 21.00 31.50 36.75 42.00 42.00 73.50
F 13.50 27.84 27.00 40.50 47.25 54.00 54.00 94.50
G 05.50 11.4 11.00 16.50 19.25 22.00 22.00 38.50
H 3 09.50 19.59 19.00 28.50 33.25 38.00 38.00 66.50
J 05.65 11.65 11.30 17.00 19.75 22.50 22.50 39.50
K 09.00 18.56 18.00 27.00 31.50 36.00 36.00 63.00
L 05.30 10.93 10.60 16.00 17.25 21.25 21.25 37.00
M 03.50 07.21 07.00 10.50 12.25 14.00 14.00 24.50
N 00.75 01.54 01.50 02.25 02.25 03.00 03.00 05.25
O 4 06.50 13.40 13.00 23.75 21.50 31.50 31.50 45.00
P 4* 11.15 22.99 22.30 38.00 40.00 50.00 45.00 80.00
Q 03.50 07.21 07.00 10.50 12.25 14.00 14.00 24.50
R 1 15.00 30.93 30.00 45.00 52.50 60.00 60.00 105.00
S 5 13.00 26.81 26.00 39.00 45.50 52.00 52.00 91.00
T 5 19.50 40.21 39.00 58.50 68.25 78.00 78.00 136.50
U 5 06.75 13.92 13.50 20.25 23.75 27.00 27.00 43.75
V 1 05.33 10.99 10.66 16.00 18.50 21.25 21.25 37.25
W 6 04.71 09.00 09.42 12.00 16.50 16.50 18.00 32.00
X 1 06.00 12.37 12.00 18.00 21.00 24.00 24.00 42.00
Y 1+ 02.40 04.95 04.80 09.00 09.50 11.00 10.00 17.50
Z 1 01.00 02.06 02.00 03.00 03.50 04.00 04.00 07.00

NOTES

1 = Minimum.
2 = Standard (minimum for prototype 2ft 9in).
3 = Maximum.
4 = Prototype dimensions are minimum.
5 = In `N’, `2mm fine’ `TT-3′, `OO’ and `O’ coarse gauges, an extra 1.8mm, 2mm, 3mm, 5mm and 7mm respectively is necessary on curves.

* = Dimensions are for straight running roads (Center to Center), for siding increase as above. (see 5)
+ = Dimensions are for straight platforms, increase on curves as necessary.

6 = In British N gauge, 9mm gauge track is used. The correct 1/148th scale track gauge works out at 9.7143mm all models are built to suit available 9mm gauge trackwork.The track gauge (W) is measured between the inside faces of the rails, not the rail centers as marked on the above diagrams.

Thanks must go to `Model Rail’ magazine for publishing the BRMSB standard dimensions for `TT3′, `HO’, `OO’, `EM’ and `O fine’ scales in the July 2000 issue which prompted me to add the dimensions for `British N gauge’ and `2mm finescale’. The N gauge dimensions are for British 1/148th scale.

Compiled by D R MacRae

 

 

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