Class 4 article

12V was a voltage standard for LEGO Trains sets from 1969 until 1990. In contrast to the older battery powered 4.5V standard, the power of the 12V system came from a mains powered DC Transformer delivered by add-on center conductor rails.

In order to reach the newer 12V standard, the older – but still co-existing – 4.5V Trains system could be upgraded by using different 12V Trains accessories.

The second generation "gray" system introduced in 1980 brought much more functionality and expansion options, with the system able to support functioning lights inside the trains, remote controlled signals, power operated points/switches, decouplers and level crossings.

No further 12V sets were released after 1986, and the 12V powered trains were replaced by 9V trains in 1991. Spare parts and accessories for the 12V system (but not complete sets) remained on sale via LEGO mail order service until 1993.

Leaflet explaining the transition from 12V to 9V made in 1993 (in French)

12V Powered Sets


Trains Accessories

Service Packs

Complete List

Image#SetNumber of piecesMinifiguresPriceRelease
11-Locomotive Traction Tires.jpg11Locomotive Traction Tyres8 1977
1104.jpg1104Battery Cables  1981
11-Locomotive Traction Tires.jpg1111Rubber Rims for Locomotive Wheels8 1977
12-Wheel Bearings for Locomotives.jpg1112Train Sliding Wheel Blocks2 1977
1119 Locomotive Piston Assemblies.jpg1119Locomotive Piston Assemblies6 1977
11-Locomotive Traction Tires.jpg1138Replacement Rubber Wheel Treads for Trains8 1981
1140-1-911824257.jpg114012V Light Brick2 1981
1146-1-911824485.jpg11464 Pushrods, 2 Cylinder Housings6 1981
1147-1-911823910.jpg11472 Light Prisms, Light Prism Holder, 2 Red and 2 Yellow Light Covers7 1981
1150 Replacement Motor 12V.jpg1150Replacement Motor 12V1 1977
12-Wheel Bearings for Locomotives.jpg12Wheel Bearings for Locomotives2 1977
12391.jpg1239Remote Control for Electric Points  1985
19-Locomotive Piston Assemblies.jpg19Locomotive Piston Assemblies6 1977
26-12V Motor.jpg2612V Motor1 1977
5069.JPEG50692 Lighting Bricks 12 V2 1987
5083-1.jpg5083Remote Control for Crossing 12V1 1989
5084-1.jpg5084Lighting Bricks 12V for Signals1 1989
0703-1.jpg70312V Replacement Motor1 1969
0704-1.jpg70412V Sleeper (Track) Contacts2 1969
0705-1.jpg705Motor Bushings4 1970
0706-1.jpg706Rail Contact Wires1 1970
0708-1.jpg7082m Extension Cord for Points1 1970
0722-2.jpg72212V Electric Train with 2 Wagons151 1970
0723-1.jpg723Diesel Locomotive95 1970
0724-1.jpg72412V Diesel Locomotive with Crane Wagon and Tipper Wagon155 1972
0725-2.jpg725Freight Train Set4252 LEGOLAND Minifigures 1974
0726-1.jpg726Western Train2873 LEGOLAND Minifigures 1976
0727-1.jpg727Locomotive134 1977
0741-1.jpg74112V Transformer1 1974
0742-1.jpg74212V Transformer - for 100V Mains1 1970
0750-1.jpg750Straight Conductor Rails8 1969
0751-1.jpg751Curved Conductor Rails8 1969
753 Automatic Right Electric Switch.jpg753Automatic Right Electric Switch4 1969
754-Automatic Left Electric Switch.jpg754Automatic Left Electric Switch4 1969
0755-1.jpg755Left and Right Points12None 1974
756-1.jpg756Electric Crossing5 1974
7715-1.jpg7715Push-Along Passenger Steam Train4495$49.501985
7725 Box.jpg7725Electric Passenger Train Set4851 1981
7727-1-1.jpg7727Freight Steam Train Set5702 1983
7730-1.jpg7730Electric Goods Train Set5122 1980
7735-1.jpg7735Freight Train Set5092 1985
7740-1.jpg7740Inter-City Passenger Train Set78610 1980
7745.jpg774512 Volt High Speed Train73610 1985
7750-1.jpg7750Steam Engine with Tender2632 1980
7755-1.jpg7755Diesel Heavy Shunting Locomotive1641 1983
7760-1-1.jpg7760Diesel Shunter Locomotive1502 1980
7823-1.jpg7823Container Crane Depot4872$45.001986
7834-1.jpg7834Level Crossing911 1980
7839-1.jpg7839Car Transport Depot3402$39.001986
7850-1.jpg7850Straight Rails32$$9.251980
7851-1.jpg7851Curved Rails32$9.251980
7854-1.jpg7854Straight Electric Rails8 1980
7855-1.jpg7855Curved Electric Rails8 1980
7856-1.jpg7856Electric Points16 1980
7857-1.jpg7857Electric Crossing5$8.751980
7858-1.jpg7858Remote Controlled Points Right 12V12 1980
7859-1.jpg7859Remote Controlled Points Left 12V12 1980
7860-1.jpg7860Remote Controlled Signal24 1980
7861-1.jpg7861Lighting Set Electric 12V28 1980
7862 Box.jpg7862Remote Controlled Decoupling16 1981
7863-1.jpg7863Remote Controlled Point Motor 12V7 1980
7864-1.jpg7864Transformer / Speed Controller 12V33 1980
7865-1.jpg7865Motor Replacement Unit for Battery or Motor-Less Trains 12V19 1980
7866-1-2.jpg7866Remote Controlled Road Crossing 12V1911 1983
7867 Box.jpg78674 Lighting Standards Electric 12V52 1983