NER M1/Q Class

The North Eastern Railway Class M1 (LNER Class D17/1) is a class of 4-4-0 steam locomotive, designed by Wilson Worsdell. 20 initial engines were built, then 30 further units were built, designated Class Q (LNER Class D17/2).
== Classification ==
Classification was complex. The NER initially classified these locomotives "M1", while a variant (with compound expansion) was classified "M". The compound was later re-classified "3CC" and the "M1" was re-classified "M".
Under LNER ownership the "M" (formerly "M1") became LNER Class D17/1 and the "3CC" (formerly "M") became LNER Class D19.
This table summarises LNER classes D17, D18 and D19, which were all very similar:
Original NER class	New NER class	LNER Class	Cylinders 	Driving wheels
M1 	M 	D17/1 	(2) 19″ × 26″ 	7′ 1¼″
Q 	- 	D17/2 	(2) 19½″ × 26″	7′ 1¼″
Q1 	- 	D18 	(2) 19½″ × 26″	7′ 7¼″
M 	3CC 	D19 	HP (1) 19″ × 26″
LP (2) 20″ × 24″	7′ 1¼″
* HP = high-pressure cylinder, LP = low-pressure cylinders
== Accidents and incidents ==
* On 4 October 1894, locomotive No. 1622 was one of two locomotives hauling a sleeping car train which overran signals and collided with a freight train that was being shunted at Castle Hills, Yorkshire. One person was killed.
: Main article: Hull Paragon rail accident
* On 14 February 1927, locomotive No. 1628 was hauling a passenger train that was in a head-on collision with another at Hull Paragon station, Yorkshire due to a signalman's error. Twelve people were killed and 24 were injured.
== Withdrawal ==
The last two D17/1s were withdrawn in 1945. Number 1629 was scrapped but number 1621 was saved for preservation.
No D17/1s passed into British Railways ownership. Two D17/2s did (BR numbers 62111 and 62112) but they were withdrawn in February 1948.
== Preservation ==
* D17/1 number 1621 is preserved at the National Railway Museum. It is at the National Railway Museum in Shildon.