Last Updated on April 10, 2017 by Dave Farquhar
When wiring a Lionel layout with multiple transformers, it helps to know the pinouts, or what posts output what voltages. Lionel published a few lists over the years but none were complete. Here is my list of 33 different Lionel transformer pinouts.
When you use multiple transformers, first you need to phase them. Once you phase them, you wire them consistently. The legends on the transformer don’t always match the internal wiring.
The common post goes to the outer rail, and you can connect the commons on all of your transformers together. Then you can run the hot post from each transformer to the center rail of the track you want to use it to control. Ideally, use a dedicated transformer for accessories that gives a useful fixed voltage with some combination of the common post and another post.
Without further ado, here’s my list of 33 Lionel transformer pinouts.
| transformer | common | track 1 | track 2 | accessories |
| 1010 | right | left | N/A | N/A |
| 1014 | right | left | N/A | N/A |
| 1015 | right | left | N/A | N/A |
| 1016 | right | left | N/A | N/A |
| 1025 | right | left | N/A | N/A |
| 1026 | right | left | N/A | N/A |
| 1032 | A | U | N/A | A-C |
| 1033 | A | U | N/A | A-C |
| 1034 | A | U | N/A | A-C |
| 1041 | A | U | N/A | N/A |
| 1042 | A | U | N/A | N/A |
| 1043 | right | left | N/A | N/A |
| 1044 | A | U | N/A | A-C |
| 1053 | right | left | N/A | N/A |
| 1063 | right | left | N/A | N/A |
| 4045 | right | left | N/A | N/A |
| 4050 | right | left | N/A | N/A |
| 4090 | U | A | N/A | B-C |
| A | A | U | N/A | A-C |
| KW | U | A | B | C-D |
| LW | A | U | N/A | A-B |
| Q | A | U | N/A | A-C |
| R | A | C | F | A-D |
| RW | A | U | N/A | B-D |
| SW | U | A | D | B or C-U |
| TW | A | U | N/A | D-A |
| V | U | A | D | B or C-U |
| VW | U | A | D | B or C-U |
| Z | U | A | D | B or C-U |
| ZW | U | A | D | B or C-U |
| S | A | U | N/A | A-C |
| 4150 | right | left | N/A | N/A |
| CW-80 | U | A | N/A | B-U |
What about Marx transformers? Here’s the general rule for those. You can use Marx and Lionel transformers together and that can be a good thing, since Marx transformers are usually really cheap.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.
when you have multiple transformers and you wire your transformers to phase them, i assume you keep them connected all the time or it is just to phase them to mark the plugs.
I do both. I have three transformers semi-permanently set up on my layout. They’re all phased and marked. I phased my spare to match the ones on my layout and marked it. As I acquired other transformers, I phased it to my spare and marked it. If I ever need to add or swap out a transformer, I can grab whichever one I want off the shelf and have it up and running in a couple of minutes.
Not everyone has the luxury of having a bunch of spare transformers, but if you find a bargain at a show or somewhere, you might as well pick it up and phase it.
THANKS FOR YOUR HELP. I THINK BIGGER WIRE IS BETTER. 12 AND 14 GAUGE ARE BETTER EVEN THOUGH SOME RAILROADERS USE 16 GAUGE. I HAVE ACQUIRED ZW TRANSFORMERS AND I REBUILD THEM. I PUT NEW COPPER CARBON ROLLERS IN THEM WHICH LAST LONGER THAN THE CARBON ONES. I INSTALL STUD DIODES TO REPLACE THE RECTIFIERS. AND I INSTALL THERMAL SEALED CIRCUIT BREAKERS. THE TRANSFORMERS WORK BETTER THAN NEW. POST WAR LIONEL TRANSFORMERS I THINK ARE BETTER. THE NEW TRANSFORMERS, SO I HEAR, HAVE A LOT OF ISSUES. THE OLD ONES DIDN’T LAST FOR 60 YEARS FOR NOTHING. THANKS AGAIN, AL
hello Dave, I heard 2 ways to phase post war Lionel transformers. One…take one wire and connect it to the “U” post of one transformer and the other end to the “U” post of the other transformer. The second way.. repeat the 1st way but add a second wire to the “A” post of both transformers. so you will have 1 wire from the “A” post to the other “A” post and 1 wire from the “U” post to the other “U” post. which way is better? and if I use the 2 wire method, I assume both wires stay connected while I am running my trains and accessories. thanks for all the posts. I read them all the time. Very useful info. thanks again, al
Thanks Al! To answer your question, you connect the common posts (whichever is common on each transformer, usually U), but you only connect the A posts for a moment for testing. Afterward, you can leave the common posts wired together. The A posts are independent so you get two independent throttles. Make sense?