Cook Defence Systems

Cook Defence Systems makes the part of an armoured vehicle that wears out fastest. Tracks take the whole weight of a fighting vehicle, drag it over rock and mud, and get replaced on a schedule measured in hundreds of kilometres, so the track supplier is a permanent fixture in a fleet's support chain rather than a one-off vendor. The company took its present form in 1994, sits in a purpose-built plant at Stanhope in County Durham with around a hundred and thirty staff, and grew out of the William Cook steel castings group in Sheffield, which also runs rail castings, general cast products for nuclear, energy, intermodal and naval customers, and an advanced manufacturing arm combining computer-controlled machining with three-dimensional printing. In June 2026 the HEICO Corporation of Florida bought eighty percent of the business, trading it as HEICO-Cook Defence, with William Cook Holdings keeping the remaining fifth and the existing management staying in place.

The track range is organised by vehicle weight. TR60 double-pin track covers platforms above fifty tonnes, TR40 handles the thirty-five to fifty tonne class, TR30 spans twenty to thirty-five tonnes in single or double-pin form, and TR20 and TR10 serve lighter vehicles. A lightweight TR40 503FS variant was developed for Ajax. Current British platforms running Cook track include Challenger 2, Ajax, Warrior, Terrier, Titan, Trojan, Stormer, Bulldog, Hunter and the CVR(T) family, and the designs are qualified or offered for a long list of foreign vehicles including Abrams, Leopard 2, Leclerc, Ariete, Altay, Puma, Ascod, CV90, Bradley, M113 and the Soviet-era types still in wide use.

Beyond track, the company designs and manufactures high-strength and armoured steel castings for fighting vehicles, drawing on the group's foundry capability, and supplies the running gear that goes with a track set: sprockets, roadwheels, idlers, rollers and the maintenance tooling crews need in the field. Spares and in-service support are sold alongside new production, which is where much of the volume actually sits.

That support role was formalised in August 2025, when the Ministry of Defence signed a three-year agreement worth up to a hundred and twenty-five million pounds for spare tracks across the British Army's principal combat vehicles, including the new Challenger 3, underpinning five million pounds of plant investment and around a hundred and twenty-five jobs in the north east. An earlier eleven million pound Challenger 2 contract ran on similar lines. The company has also become one of the more consequential quiet suppliers to Ukraine, manufacturing spare tracks both for donated British armoured vehicles and for the Soviet-designed fleet the Ukrainian army still runs, work that depends on holding tooling and metallurgy for patterns nobody else in Western Europe kept. That inventory of patterns is the real asset. Steel, heat treatment and a track record on qualified platforms are hard to restart once a foundry closes.