List of GWR classes. This list does not include absorbed locos.

'Ariadne' Class 0-6-0
'Banking' Class 0-6-0ST
'Bogie' Class 4-4-0ST
'Caesar' Class 0-6-0
'Caliph' Class 0-6-0
'Firefly' Class 2-2-2
'Hercules' Class 0-6-0
'Iron Duke' Class 4-2-2
'Leo' Class 2-4-0
'Metropolitan' ('Metro') Class 2-4-0T
'Premier' Class 0-6-0
'Prince' Class 2-2-2
'Pyracmon' Class 0-6-0
'Sir Watkin' Class 0-6-0T
'Star' Class 2-2-2
'Sun' class 2-2-2
'Victoria' class 2-4-0
'Waverley' class 4-4-0
131 Class 0-6-0
316 Class 0-6-0
Hawthorn class 2-4-0, later 2-4-0ST
'Swindon' class 0-6-0
'Rover' class 4-2-2
Standard goods 0-6-0
1076 Class 0-6-0ST
'Queen/Sir Alexander' Class 2-2-2
'Sir Daniel' Class 2-2-2
7/8/30/32/110 Class 2-2-2
17 Class 2-4-0ST
56/717 Class 2-4-0
111 Class 2-4-0
302 Class 0-6-0ST
360 Class 0-6-0
388 Class 'Standard Goods' 0-6-0
439 'Bicycle' Class 2-4-0
455 Class 2-4-0T
481 Class 2-4-0
806 Class 2-4-0
927 Class 'Coal Goods' 0-6-0
1076 Class 'Buffalo' 0-6-0ST
34 Class 0-6-0
108 Class 2-4-0
119 Class 0-6-0ST
322 Class 0-6-0ST
517 Class 0-4-2T
633 Class 0-6-0T
645 Class 0-6-0ST
655 Class 0-6-0ST
850 Class 0-6-0ST
1016 Class 0-6-0ST
1501 Class 0-6-0ST
1901 Class 0-6-0ST
Nos 8, 14, 16 2-4-0  (not sure what this is yet)
3001 class 2-2-2
3501 class 2-4-0T
3521 class 0-4-2ST, later 0-4-4T
No. 1 4-4-0T later 2-4-0T
Nos. 7, 8, 14, 16 experimental 2-4-0, later 4-4-0
No. 13 2-4-2T, later 4-4-0ST
Nos. 17-19 0-6-4T crane tanks
No. 36 4-6-0
No. 45 0-4-0ST
'River' (69) 2-4-0
'Sharpies/Cobham' (157) 2-4-0
1661 Class 0-6-0ST
1813 Class 0-6-0ST
1854 Class 0-6-0ST
2021 Class 0-6-0ST
2201 Class 2-4-0
2301 Class 'Dean goods' 0-6-0
2361 Class 0-6-0
2600 Class 'Aberdare' 2-6-0
2721 Class 0-6-0ST
3001 Class 2-2-2, later 4-2-2
3031 Class 4-2-2
3201 Class 2-4-0
3206 Class 'Barnum' 2-4-0
3226 Class 2-4-0
3232 Class 2-4-0
3252 Class 'Duke' 4-4-0
3300 Class 'Bulldog' and 'Bird' 4-4-0
3501 Class ex-broad gauge 2-4-0T
3521 Class 0-4-2T, later 0-4-4T then 4-4-0 (some tank locomotives ex-broad gauge)
3571 Class 0-4-2T
3600 Class 2-4-2T
4100 Class 'Badminton' 4-4-0
4120 Class 'Atbara' 4-4-0
4149 Class 'Flower' 4-4-0
The Great Bear (4-6-2): 111
1361 Class (0-6-0ST): 1361–1365
'County Tank' Class (4-4-2T): 2221–2250
2800 Class (2-8-0): 2800–2883
'Saint' Class (4-6-0): 2900–2998
3100 Class (2-6-2T): 31xx (later 51xx)
3150 Class (2-6-2T): 3150–3190
'City' Class (4-4-0): 3700–3719
'County' Class (4-4-0): 3800–3839
'Star' Class (4-6-0): 4000–4072
4200 Class (2-8-0T): 4200–4299, 5200–5204
4300 Class (2-6-0): 43xx, 53xx, 63xx, 73xx, 93xx
4400 Class (2-6-2T): 4400–4410
4500 Class (2-6-2T): 4500–4574
4700 Class (2-8-0): 4700–4708
Steam Railmotors
1101 Class (0-4-0T): 1101–1106
1366 Class (0-6-0PT): 1366–1371
1400 Class (0-4-2T): 1400–1474 (renumbered 1946 from corresponding numbers in 48xx group)
'Collett Goods' 2251 Class 0-6-0: 2200–2299, 3200–3219
2884 Class (2-8-0): 2884–2899, 3800–3864
3100 Class (2-6-2T): 3100–3104
'Earl' or 'Dukedog' Class (4-4-0): 3200–3228, 3265 (later 9000–9028, 9065)
'Castle' Class (4-6-0): 4073–4099, 5000–5099, 7000–7037
4575 Class (2-6-2T): 4575–4599, 5500–5574
4800 Class (0-4-2T): 4800–4874 (later 1400–1474)
Hall Class (4-6-0): 4900–4999, 5900–5999, 6900–6958
5101 Class (2-6-2T): 5101–5199, 4100–4179
5205 Class (2-8-0T): 5205–5264
5400 Class (0-6-0PT): 5400–5424
5600 Class (0-6-2T): 5600–5699, 6600–6699
5700 Class (0-6-0PT): 57xx, 67xx, 77xx, 87xx, 97xx, 36xx, 37xx, 46xx, 96xx
5800 Class (0-4-2T): 5800–5819
'King' Class (4-6-0): 6000–6029
6100 Class (2-6-2T): 6100–6169
6400 Class (0-6-0PT): 6400–6439
'Grange' Class (4-6-0): 6800–6879
7200 Class (2-8-2T): 7200–7253
7400 Class (0-6-0PT): 7400–7449
'Manor' Class (4-6-0): 7800–7829
8100 Class (2-6-2T): 8100–8109
GWR diesel shunters: Diesel shunters 1 and 2
GWR railcars: Diesel railcars 1–38
'County' Class (4-6-0): 1000–1029
1500 Class (0-6-0PT): 1500–1509
1600 Class (0-6-0PT): 1600–1669
'Modified Hall' Class (4-6-0): 6959–6999, 7900–7929
9400 Class (0-6-0PT): 9400–9499, 8400–8499, 3400–3409
GWR diesel shunters: Diesel shunters 501-507 (Introduced as BR 15101-15107)
GWR Gas turbine-electric locomotives, introduced as British Rail 18000 and British Rail 18100