- 4 Foot
- See Four Foot

- 4-cyl. Compound Coal Locomotive Class
- See Webb's
0-8-0 B Class .
- 4-cyl. Compound Goods Locomotive Class
- Offical name for 1400 4-6-0 Locomotive class
(a.k.a. “Bill Bailey”).
- 4ft 6in 2-4-0 Tank Locomotive Class
- Designed by Mr. Webb
, 50 of this class were built between 1876—80. In original condition these engines had condensing apparatus , half cab , wooden brake blocks and buffer beams , horizontal smoke box door and Webb closed safety valves .
- 4ft 6in 2-4-2 Tank Locomotive Class
- The 4ft 6in 2-4-0 Tank were designed by Mr. Webb
to give greater capacity that the 2-4-0 tanks. Eventually, there were 220 of them, 180 built new in 1879—90 and 40 built as replacements of 2-4-0 tanks in 1895—8. They had condensing apparatus , full cab , wooden brake blocks and buffer beams , horizontal smoke box door and Webb closed safety valves .
- 4ft Shunter 0-4-0T Locomotive Class
- Ramsbottom
introduced this class of 0-4-0 saddle tank in December 1863. They were the first engines to have cast-iron H-section driving wheels , and coupling rods with solid ends, but otherwise had the usual Ramsbottom features, ornamental chimney top , safety valves wooden buffer beams and brake blocks . 
- 5ft 6in 2-4-2 Tank Locomotive Class
- These were designed to replace the ‘Samson’
2-4-0s on local and branch line passenger work. They were the tank engine counterparts of the ‘Precusor’ class 2-4-0 and 160 were built in 1890—7. They had steel buffer beams , metal brake blocks , and circular smoke box door .
- 5ft 6in 4-w. Coupled Passenger Tank Locomotive Class
- The official name of the “Precursor tank” class
.
- 6 Foot
- See Six Foot

- 6-w.c. Coal Locomotive Class
- The official name of the “Coal Engine” class
.
- 6ft 6in Curved Link Passenger Engine 2-4-0
- Better known by the name of the first engine in the class ‘Newton’
.
- 6ft Curved Link Passenger Engine 2-4-0
- Better known by the name of the first engine in the class ‘Samson’
.
- 7ft 6in Single 2-2-2 Locomotive Class
- Official name of the locomotive class generally known as ‘Problem’ class
.
- 8-w.c. Coal 18½in Small boiler Locomotive Class
- Offical name of the C1
0-8-0 Locomotive Class
- 8-w.c. Coal 19½in Small boiler Locomotive Class
- Offical name of the D
0-8-0 Locomotive Class.
- 8-w.c. Coal 19in Large boiler Locomotive Class
- Offical name of the F
0-8-0 Locomotive Class
- 8-w.c. Coal 20½in Non-superheat Locomotive Class
- Offical name of the F
0-8-0 Locomotive Class
- 8-w.c. Coal 20in Superheat Locomotive Class
- Offical name of the G1
0-8-0 Locomotive Class.
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