| Great Northern Railway Classes PG, QG, QLG and QNG | |
| Powertype: | Steam |
| Designer: | C. Clifford |
| Builddate: | 1899—1911 |
| Totalproduction: | 28 |
| Whytetype: | 0-6-0 |
| Driverdiameter: | 4feet |
| Locoweight: | — |
| Boilerpressure: | 1752NaN2 |
| Cylindercount: | Two, inside |
| Tractiveeffort: | 198802NaN2−240652NaN2 |
| Trainheating: | steam |
| Operator: | GNR(I) → UTA → CIÉ |
| Numinclass: | 28 |
Great Northern Railway Classes PG, QG, QLG and QNG were a series of 0-6-0 freight locomotives introduced from 1899 by Charles Clifford.
The PG class was introduced in December 1899 by Charles Clifford with 4inchesft7inchesin (ftin) driving wheels and NaNinchesx24inchesin (xin) cylinders. The QG's introduced in 1904 were 1feet longer than the PG with NaNinchesx26inchesin (xin) cylinders weighed in 2 tons heavier. The key changed with the QLG class introduced in 1906 was a 4inchesft9inchesin (ftin) wide boiler.