Thomas and Friends Train Assortment

As a part of the relaunch, almost every aspect of the basic engineering was overhauled. The track system was changed for the first time since TrackMaster Revolution in 2014, which allows for derailed rolling stock to automatically rerail themselves. The engines now use one-way magnets instead of plastic couplers, the levers on top of the engines were replaced by buttons, and the bodyshells are smaller than both the All Engines Go and 80th Anniversary ranges.

The range also introduced two new chassis types: a short chassis for smaller engines, and a long chassis with a set of leading wheels at the front and occasionally a false set of trailing wheels at the back for larger engines. The latter also features a drawbar at the back which permanently couples it to the engine's tender or rolling stock. Both chassis run on only one AAA battery, instead of two AAA batteries or a single AA. The smaller chassis have the engines' running boards and bufferbeams mounted directly onto them, while like the previous motorised ranges, the bufferbeams and footplates for the large chassis engines are attached to the upper body shell and not the chassis.