Taff Vale Railway O4 class Builders and numbering Builders and numbering

| Year_ | Quantity | Manufacturer | Serial_Number | TVR_Numbers | GWR_Numbers |
|---|---|---|---|---|---|
| 1907 | 7 | Manning Wardle | 1698–1704 | 38, 43, 59, 67–69, 94 | 285, 287, 293–295, 420, 296 |
| 1908 | 7 | Beyer, Peacock & Co. | 5095–5101 | 39, 95, 97, 98, 101, 102, 104 | 286, 297–302 |
| 1908 | 7 | Beyer, Peacock & Co. | 5127–5133 | 6, 9, 48, 56, 58, 105, 111 | 280, 282, 289, 291, 292, 236, 314 |
| 1910 | 10 | Beyer, Peacock & Co. | 5384–5393 | 13, 49, 112–116, 118, 119, 121 | 409, 290, 315, 317–321, 324, 333 |
| 1910 | 10 | Vulcan Foundry | 2529–2538 | 1, 28, 8, 17, 35, 36, 46, 108–110 | 278, 279, 281, 283, 284, 414, 288, 310, 311, 313 |