Unbuilt Locomotive Classes

There have been a number of TOPS class numbers assigned to proposed locomotives that have not been built for one reason or another.

Type 1

 * Class 18 - A proposed new Type 1 locomotive proposed in the mid 1980s. A 1988 proposal was for a 6-wheeled 800 hp locomotive with a maximum speed of 50 mph, similar in concept to class 14 . No prototype was constructed.

Type 3

 * Class 38 - Projected classification for new generation of Type 3 freight locomotives in the 1980s. The Class 38 was dropped in favour of the Class 60.

Type 4

 * Class 41 - The third use of Class 41 was for a proposed class of Class 60 locomotives with 2,500 hp engines in the early 1990s.
 * Class 48 - The second use of Class 48 was for a new class of freight locomotive in the mid 1980s.

Type 5

 * Class 51 - Projected classification for the proposed "Super Deltic" locomotive intended as a follow on from the Class 50 and Class 55.
 * Class 62 - Projected classification for proposed Type 5 coal train locomotives in the early 1990s. (LAter became the Class 66)
 * Class 65 - Projected classification for proposed 4,000 hp freight working locomotive intended for liner trains.

DC Locomotives

 * Class 75 - Spare classification for projected "super electro-diesel" follow on from Class 73 and Class 74.

AC Locomotives

 * Class 88 - The first use of Class 88 was for a proposed electric version of the Class 58, powered through 25 kV AC from overhead wire.
 * Class 93 - Proposed electric locomotive for use on the West Coast Main Line as part of the InterCity 250 project. This would have been simlar to the Class 91 and there set up.