The Class 43 is a diesel locomotive and the main component of the Intercity 125 sets, alongside a set of British Rail Colour scheme on the front, while the window sits large and streamlined, with a single wiper. The side of the train has a large ventilation shaft on it, used for engine cooling. Class 43s come in two batches, the Class 43/0, and the Class 43/1, the latter being a converted DVT, while the first ones where built by British Rail originally. It is known by railfans as the HST.