The museum's collection is mostly of larger stationary diesel engines, as used for generating sets and pumping stations.

The museum houses over 200 tons of working engines in nine halls and in 2020 was in the process of creating a new steam hall to house a 1903, J & E Wood, 500 hp tandem compound along with an 1879, John Penn, twin cylinder oscillating paddle steamer (ex Empress) as well as a number of smaller engines including the only surviving Petter steam engine.

[1] A 1901, 140 bhp three cylinder Willans engine generating set had been used until 1957 at the Maples furniture shop in London.

On retirement this had been placed on display at the original Willans factory in Rugby[2][3] One of the museum's most unusual exhibits was a 'Pocket Power Station', powered by a Bristol Proteus gas turbine engine.

[4][5] The regional electricity board installed several 2.7MW, remote-operated, generation sets for peak load powered by the Proteus.