| Highland Railway K class | |
| Powertype: | Steam |
| Designer: | Peter Drummond |
| Builder: | Dübs & Co. (10) North British Locomotive Co. (2) |
| Serialnumber: | Dübs: 3842–3847, 4240–4243 NBL: 17896–17897 |
| Builddate: | 1900 (6), 1902 (4), 1907 (2) |
| Totalproduction: | 12 |
| Whytetype: | 0-6-0 |
| Uicclass: | C n2g |
| Driverdiameter: | 5feet |
| Locoweight: | 43LT |
| Firearea: | 20.5square feet |
| Boiler: | Same as class C |
| Boilerpressure: | 175psi |
| Cylindercount: | Two (inside) |
| Cylindersize: | NaNx |
| Valvegear: | Stephenson |
| Tractiveeffort: | 214692NaN2 |
| Operator: | Highland Railway →London, Midland & Scottish →British Railways |
| Operatorclass: | HR: K |
| Powerclass: | LMS/BR: 3F |
| Withdrawndate: | 1936, 1946–1952 |
| Disposition: | All scrapped |
The Highland Railway K class were the only class of 0-6-0 tender locomotives built for the Highland Railway. They were introduced in 1900, to the design of Peter Drummond. The class were known as 'Barneys'.
They were standard designs for British practice of the time, with inside cylinders and 5feet diameter driving wheels.
The first six (Nos. 134 to 139) were built by Dübs and Company in 1900. These had inside bearing double bogie tenders, rather like the watercart designs brother Dugald was supplying on the London and South Western Railway. These were later transferred to C and U class (Ben) locomotives.
Four more (Nos. 18 to 21) were supplied by Dübs in 1902. These lacked the watercart tenders but had cross water tubes in the firebox. No. 21 is recorded as retaining this boiler in unmodified form until 1934.
A final pair (Nos. 36 and 55) was built by the North British Locomotive Company in 1907.
All passed into London Midland and Scottish Railway (LMS) ownership in 1923. The first was withdrawn in 1936, but all others stayed in service until 10 years later.
Seven survived into British Railways (BR) ownership in 1948. The last was withdrawn in 1952 and all were scrapped.
| 134 | 3842 | 17693 | 57693 | align=left | Withdrawn before BR number applied | ||||
| 135 | 3843 | 17694 | 57694 | align=left | Withdrawn before BR number applied | ||||
| 136 | 3844 | 17695 | 57695 | align=left | |||||
| 137 | 3845 | 17696 | — | align=left | |||||
| 138 | 3846 | 17697 | 57697 | align=left | Had stovepipe chimney | ||||
| 139 | 3847 | 17698 | 57698 | align=left | |||||
| 18 | 4240 | 17699 | 57699 | align=left | Withdrawn before BR number applied | ||||
| 19 | 4241 | 17700 | — | align=left | |||||
| 20 | 4242 | 17701 | — | align=left | |||||
| 21 | 4243 | 17702 | 57702 | align=left | Withdrawn before BR number applied | ||||
| 36 | 17896 | 17703 | — | align=left | |||||
| 55 | 17897 | 17704 | — | align=left |