Obtuse crossings (all standards)




Figure 1. 1 in 8 obtuse crossing in bullhead rail.

Dimensions for obtuse crossings from 1 in 3 to 1 in 8

Crossing angle (1 in β) Wing rail (mm) Check rail (mm) S7 O fine O coarse
N-N (mm) Point rail (mm) N-N (mm) Point rail (mm) N-N (mm) Point rail (mm)
3 94.5 100.9 8.8 129.2 13.3 124.8 16.0 122.0
3½ 100.9 107.9 10.3 76.8 15.4 68.1 18.6 64.9
4 100.9 107.9 11.7 73.0 17.6 67.1 21.3 63.4
4½ 100.9 107.9 13.2 89.0 19.8 82.4 23.9 78.3
5 100.9 107.9 14.6 104.9 22.0 97.5 26.5 93.0
5½ 100.9 107.9 16.1 120.8 24.2 112.7 29.1 107.7
6 100.9 107.9 17.5 136.7 26.3 127.9 31.7 122.5
6½ 107.9 114.9 18.9 97.0 28.4 87.5 34.2 81.7
7 107.9 114.9 20.4 93.8 30.5 83.6 36.8 77.3
8 107.9 114.9 23.3 92.3 34.9 86.7 42.1 74.2

Notes

  1. On the prototype the point rail of a 1 in 3 obtuse crossing is common with the wing rail of the adjacent common crossing. For two rail electrification a gap will be required.
  2. From 1 in 6½, a closure rail was inserted between the point rail of the obtuse crossing and the wing rail of the common crossing. In model form, this is better fitted at site and dimensions have not been given. The values of N-N are based on a prototype blunt nose of ¾in, although some companies used ½in for1 in 6½ and above.




Figure 2. 1 in 8 obtuse crossing drawn for fine standard.

Chairing of bullhead obtuse crossings

Crossing (1 in β)
1½ A A
2 A A
2½ A A
3 A A
3½ A A
4 B A A B
4½ B A A B
5 B A A B
5½ B A K A B
6 B A K A B
6½ B A K A B
7 B A K A B
7½ C B A K A B C
8 C B A K A B C

Baseplates for flat bottom crossings

Crossing (1 in β)
4 C B A A B C
4½ C B A A B C
5 C B A K A B C
5½ C B A K A B C
6 C B A K A B C
6½ C B A K A B C
7 C B A K A B C
7½ C B A K A B C
8 C B A K A B C



This article was compiled by M. Holland for the Gauge O Guild Manual. It was adapted for the GOGWiki by Nick Baines.