The following companies built diesel railcars & railbuses during the first generation era. The number of each type built that is covered by this website is shown in brackets:

AC Cars - 5 vehicles

• Railbuses (5)

Associated Commercial Vehicles (ACV) - 11 vehicles

• 4-wheeled railcars (11) (these vehicles also sometimes referred to as built by AEC/BUT)

Birmingham Railway Carriage & Wagon (BRC&W) - 437 vehicles

• Class 104 (302)
• Class 110 (90)
• Class 118 (45)

Two BRC&W coaches would be converted to the Davey-Paxman diesel electric unit.

Bristol Commercial Vehicles (with Eastern Coach Works) - 2 vehicles

• Railbuses (2)

British United Traction (BUT) - 56 vehicles

• 4-wheeled railcars (11) - some as ACV
• Class 103 (40) (built under the Park Royal brand by Crossley)
• Railbuses (5) (built under the Park Royal brand)

Cravens - 405 vehicles

• Class 105 (302)
• Class 112 (50)
• Class 113 (50)
• Class 129 (3)

Derby Works (British Railways) - 1396 vehicles

• Derby Lightweights (hydraulic) (16)
• Derby Lightweights (mechanical) (201)
• Battery Multiple Unit (2)
• 50000/56000 (2)
• Paxman testbed conversion (2)
• Class 107 (78)
• Class 108 (333)
• Class 114 (98)
• Class 115 (164)
• Class 116 (320)
• Class 125 (60)
• Class 127 (120)

Eastern Coach Works (with Bristol Commercial Vehicles) - 2 vehicles

• Railbuses (2)

Gloucester Railway Carriage & Wagon (GRC&W) - 200 vehicles

• Class 100 (80)
• Class 119 (81)
• Class 122 (29)
• Class 128 (10)

Metropolitan Cammell - 796 vehicles

• Met-Camm Lightweights (72)
• Class 101 (620)
• Class 111 (68)
• Blue Pullman (36)

Park Royal - 56 vehicles

• 4-wheeled railcars (11) (for ACV/BUT)
• Class 103 (40) (by Crossley for BUT)
• Railbuses (5) (for BUT)

Pressed Steel - 149 vehicles

• Class 117 (123)
• Class 121 (26)

Swindon Works (British Railways) - 417 vehicles

• Inter-City 79xxx series (64)
• Class 120 (194)
• Class 123 (40)
• Class 124 (51)
• Class 126 (66)

Waggon und Maschinenbau - 5 vehicles

• Railbuses (5)

Wickham - 16 vehicles

• Class 109 (10)
• Railbuses (5 plus one non-passenger)