| P&RR C1a class | |
|---|---|
| Power type | Steam |
| Builder | Reading Company |
| Build date | 1915 |
| Total produced | 4 |
| Configuration | 4-4-4 |
| Gauge | 4 ft 8 1⁄2 in (1,435 mm) |
| Driver diameter | 6 ft 8 in (2.032 m) |
| Locomotive weight | 230,800 lb (104,700 kg) |
| Fuel type | Coal |
| Boiler pressure | 240 psi (1.65 MPa) |
| Cylinders | Two, outside |
| Cylinder size | 23.5 × 26 in (597 × 660 mm) |
| Tractive effort | 36,604 lbf (162.82 kN) |
| Withdrawn | 1916 |
The C1a Class were a type of 4-4-4 steam locomotive built for the Philadelphia and Reading Railway in 1915. Four locomotives were built, road numbers #110-113. They used front and rear trucks that were effectively identical. During a year of operation, they proved to be quite unstable; after that year, they were rebuilt to 4-4-2 "Atlantic" locomotives, reclassified as P7sa, and renumbered #350-353.