| Year | 1950 |
| Date | 31-Aug |
| Volume | 103 |
| Issue | 2,571 |
| Page | 336 |
| Category | Locomotive |
| Part | |
| Title | Twin Sisters. Two 5-in. gauge locomotives, exactly alike externally but very different internally |
| Author | J.I.Austen-Walton |
| Notes | Boring the cylinders, the boring bar, chuck or faceplate boring, measuring the bore, bolting and port faces, machining versus lapped bores, steam chests |