9th series No. 17, 1 boiler band, short tapered boiler casting. The motor is stamped 1918 - note the smooth casting on the steam chest as opposed to the example below.

This loco has 1927 on the motor plate - note this one has the dual steam chest casting and the additional tank in front of the cab.

This one is stamped as a No. 17 but has the same casting as a No. 20 from that time period.