| Year | 1950 |
| Date | 14-Sep |
| Volume | 103 |
| Issue | 2,573 |
| Page | 418 |
| Category | Locomotive |
| Part | |
| Title | Twin Sisters. Two 5-in. gauge locomotives, exactly alike externally but very different internally |
| Author | J.I.Austen-Walton |
| Notes | Cylinder covers, pistons and rods, port passage and pipe areas, slide-valves and rods, this week's afterthought |