LNER Class Y11 was a class of petrol powered 0-4-0 locomotives built by Motor Rail & Tram Car Company Limited under their Simplex brand and introduced in the years 1919–1925, operating after its formation in 1922 on the London and North Eastern Railway (LNER). Their British Railways numbers were 15097-15099.
- Works no. 1931, LNER no. 8430, re-numbered 8188, BR no. 15098 or 68188
- Works no. 2037, LNER no. 8431, re-numbered 8189, BR no. 15099 or 68189
- Works no. 2126, LNER no. ED/L4, BR no. 15097
- Unknown built date acquired by LNER 1925 (ex-Preston Water Works, Lancashire), withdrawn in 1950
- The RCTS document BRITISH RAILWAYS, NORTH EASTERN REGION, LOCOMOTIVE ALLOCATION, 6th May 1950 records this locomotive as working at West Hartlepool (Creosote Works).
- Wheel arrangement: 0-4-0
- Weight: 8 tons 0 cwt
- Wheel diameter: 3 ft 1in
- Min curve negotiable: 1 chain
- Engine type: Dorman 4JO (petrol)
- Engine output: 40 hp
- Power at rail: 24 hp
- Maximum speed: 7½ mph
- Brake type: Air on loco, no train brake
- Route Availability: 1
- Heating type: Not fitted
- Multiple coupling type: Not fitted
- Transmission: Mechanical, 2-speed Dixon Abbot
None of the LNER Class Y11 locomotives has been preserved but several similar ones have, including:
Nottingham Transport Heritage Centre also has another Simplex numbered 15100. This is probably an "imaginary" British Railways number, continuing from 15099.