GWR letters and colours?

[Bruces]

hi,
I was wondering if someone could tell me what the letters and colours on the side of the cab mean of GWR loco's?

[dgraw]

I assume you are referring to the letters in coloured circles above the number plate.
I am not the best to explain and could be slightly off, but they indicate the weight of a locomotive, A being lightest and DD (only applied to the Kings) being the heaviest. Because as you will understand a King wouldn't be able to cross lightly laid Branch Lines built for light engines.
It is basically a simple way of classifying locomotive weight.

I hope this helps.

[davidaward]

The colour discs refer to the loco's axle loading classification and to what routes that rating is allowed to travel over. ON some lines locoss of a higher code were allowed at restricted speed.

Heaviest is double red (Kings only)
Single red (eg 47XX, Hall, Grange, Castle, 56XX)
Blue (eg Manor, Mogul, 28XX, Large Prairie)
lightest is yellow- this classification means the engines are free to roam anywhere on the GWR system! (eg Collett Goods, small Prairie, 57XX, 64xx pannier)

The letter on the disc refers to its power classification according to which tractive effort group it was in.

E 33,001-38,000 (eg King, 47XX, 72XX)
D 25,001-33,000 (eg Manor, Hall, large prairie, 56XX, )
C 20,510-25,000 (eg, small prairie, 57XX, 94XX)
B 18,501-20,500 (eg Collett Goods, Dean Goods)
A 16,500-18,500 (eg 16XX pannier, 64XX pannier)

Ungrouped below 16,500 (eg 14XX, Vale of Rheidol 2-6-2t)

The classification was carried on from GWR into BR days