What does the Challenger 2 have in common with the Challenger 1?
Challenger 1 The FV4030/4 Challenger 1 is a British main battle tank (MBT) used by the British Army from 1983 to the mid-1990s, when it was superseded by the Challenger 2. It is also currently used by the Royal Jordanian Army as its main battle tank after heavy modifications. The variants for the Jordanian military are to be upgraded using the unmanned Falcon turret.
Comet (railcar) The Comet railcar is a class of locomotive-hauled railcars that was first designed in the late 1960s by Pullman-Standard as a modern commuter car for North American rail lines. Later, the Comet moniker was adopted by New Jersey Transit for all of its non-powered single level commuter coaches. Additional series of cars bearing the Comet name, based on the original design, have since been built by Bombardier Transportation and Alstom. The successful design was adopted by numerous commuter agencies.