The Track Marshall TM1600 was the first power shift TM shovel, originally developed at the Fowler works in Leeds, England as the TM15P, one of three prototypes. Also built was a manual transmission version and a hydrostatic version, at a similar time, the Track Marshall TM80 was built, as a one off, later much modified as the Track Marshall TM85. Also built was the only Track Marshall TM1300, a 1.25cu.yd. loader using many 1600 parts, a Perkins 4.236 engine and TM56 chains. It was not proceeded with due to build cost close to the 1600. The manual machine was converted to powershift and, following testing, the TM1600 was launched. Machine one was sold, while machine number two was used to build the first Track Marshall TM1700, which differed only in the steering control system that used transmission oil to operate the caliper release intensifier and the brake rams. Similar changes were made to the 85 launched as the 85B. The hydrostatic machine was sold as a non runner, to the Nottingham firm that bought the two prototypes and the 1300. The prototypes differed from the launched machines in having changes to the idler, the bonnet and hard nose, the rams were slightly smaller and many minor changes as a result of testing..in total around 230 powershift shovels were built, mostly at Gainsborough, a few survive.