2 ENGINES IN TANDEM..HOW IS IT DONE?

[Anonymous]

I would like to link two diesel engines in tandem. I do not use digital control. How can they be linked to move together? I know there are 'sets' of A-A or A-B. but what if I purchase the two independently? I understand that some engines have a switch to lock in forward. Thanks.

[cnw1995]

As you can guess, this is easier with TMCC or DCS. And some engine types go prototypically together as you noted, with A-A and A-B or variations thereupon. But you can do whatever you want with your railroad and, in my experience, with any two engines that you can both lock to go forward, couple together and then fire up the transformer. You'll need a fair amount of power. Depending on the motors they may run a bit unevenly. There are ways of rewiring the engines to do this quasi-permanently as well.

[3railguy]

Who is the manufacturer and what models are they?

[Anonymous]

This is a hypothetical question before I foolishly purchase something. one ground rule I assume is 2 of the same model and brand. I have a Lionel FM trainmaster that I would match if I found a used one if in fact they will work together. thanks

[ChiefEagles]

Post war Lionel with e'unit, I have strapped 3 together to one e'unit. That way they did not get out of sequence. Ran great. Only problem was the cables running from one unit to the others. Used a small 4 wire cable. Can lock them into forward with the e'unit lever but I do not like that. Newer trains like the Williams with electronic reversing unit, hook them together and they do fine. If one does get out of sequnce, hold the power off for a few seconds, they start in forward.

Look at the back three engines, you can see the cables. Front was dummy.

Click on picture to enlarge.

[daan]

The Chief's option is probably the best if you want the e-unit working. The mechanical e-unit can handle the draw of 3 motors easily. If you want a permanent setup that way, you could remove the clawcouplers and use a piece of cirquitry board with 4 leads, where you solder the wires on to. Afterwards paint it black and fit between the engines as a coupler. The wires are all inside the engine that way and the coupler passes the power and driving direction to the motors.

[lionelsoni]

Lionel rated their e-unit for 4 motors.

One problem with running simple can-motor locomotives in tandem is that the permanent-magnet motors used, unless overloaded, want to run at a speed proportional to the voltage. Since both locomotives are getting the same voltage, if one is designed to be faster than the other, that one will tend to do all the work, and even be slowed down by the slower one acting as a generator--a sort of undesirable dynamic brake. So it's a good idea to check a pair of such locomotives by running them together on the same track but uncoupled to see whether their speeds are similar, before coupling them.

[Anonymous]

This forum is very helpful. More detail: I have two FM trainmasters (6-18301 & 6-18309) with pullmor motors and (I think ) an 'e unit'. 'Dr. Tinker' , who I visited at our local Greenburg show, suggested that I wire the 4 pullmors to one 'e unit'. Has anyone had expereince with this?

[lionelsoni]

You can do this in a way that still allows you to run the two units separately. All you do is connect together, through a tether, the two armature wires and the ungrounded field wire. These are probably already connected together between the two motors within the locomotive. I don't know about locomotives as late as yours; but the postwar locomotives had a black three-conductor zip-cord cable directly between the motors. Those are the three wires to connect between locomotives.

It is also a good idea to connect the pickups of the two locomotives together, to take advantage of the low probability that all four pickups will be open at the same time.

To use the locomotives in tandem, first cycle one locomotive into the neutral position, then turn its e-unit off. This leaves all three of those motor connections disconnected from that locomotive's e-unit. Then plug the tether together. The e-unit of the other locomotive will then operate all four motors.