Tr 156 is an example of the heaviest Tr's on Tranz Rail's system developing some 150 hp and weighing 20 tons. Seven of these locomotives were built by W G Bagnall Ltd and introduced to service in 1956-57.
Locomotives No. 150 to 155 had McLaren engines while 155 and 156 had Gardner engines, all with a four speed gearbox. The first five locomotives were later re-engined with Gardner engines driving through a torque converter. Like most of the Tr's, in recent years the Bagnalls have been gradually withdrawn from service.
Tr 156 was sold to the Canterbury Railway Society and moved on site in February 1999. It is now used for heavier shunting and hauling some passenger trains.
