| Queensland Railways 4D11½ Abt class | |
| Powertype: | Steam |
| Builder: | Dübs & Co |
| Serialnumber: | 3619, 3620 |
| Builddate: | 1898 |
| Totalproduction: | 2 |
| Whytetype: | 0-4-2RT |
| Fueltype: | Coal |
| Watercap: | 600impgal |
| Cylindercount: | 2 |
| Cylindersize: | 11.5x |
| Locobrakes: | Westinghouse air Le Chatlier |
| Operator: | Queensland Railways |
| Fleetnumbers: | 339, 340 |
| Disposition: | both scrapped |
The Queensland Railways 4D11½ Abt class locomotive was a class of 0-4-2RT steam locomotives operated by the Queensland Railways.
In October 1898, two Dübs & Co locomotives entered service. Per Queensland Railway's classification system they were designated the 4D11½ Abt class, the 4 representing the number of driving wheels, the D that it was a tank locomotive, and the 11½ the cylinder diameter in inches.
They were built to assist conventional locomotives up and down a steeply graded rack railway section of the Central Western line at Mount Morgan.[1]
| Number | Works number | In service | Condemned |
|---|---|---|---|
| 339 | 3619 | October 1898 | September 1916 |
| 340 | 3620 | October 1898 | December 1922 |