2 Motors on the front, or one on each end

[Nicolas]

I have recently built a custom train (pictures and info of the train itself to come in the next month). When building it, I put a 9V motor at each end. I was wondering though, is it better to have one motor on each end or 2 at the front?

Has anyone tested this scenario out or know which should work better?

[LEGO Guy Bri]

I have done this with my metroliner, One at both ends provides the same power at one with two at one end. One at each end is the ideal setup if your track has an incline. One to push, one to pull. However, if your train isn't too long; 5-7 cars two at one end would be fine IF adding a 9v at the back would look weird. That being said I have read that two 9v engines on the same car end up dirtying the track faster than having one on each individual train car (i.e. 2 BNSFs w/ one motor on each, or similar setup) If you run long trains on flat surface it doesn't really matter where the motors are located until you get into issues with the magnet strength and part of the train getting left behind. Any further questions or if you'd like my personal opinion on your train specifically, just let me know whatcha hauln (# of cars)! Hope this helps

[AussieJimbo]

Definitely motors in locos at either end like in real life. Both my extended RC and PF passenger trains are set up this way.

Better for inclines and curves because usually you only have one motor dealing with a tricky spot in the track. Also helps avoid a longer trains splitting and just makes them run smoother overall.

:classic:

[TaltosVT]

If you run one on either end, be sure to run the faster motor in the front. Otherwise you end up pushing your train into itself.

That said, I've run two motors on a single locomotive for years and never had any trouble.

-Elroy

[AussieJimbo]

If you run one on either end, be sure to run the faster motor in the front. Otherwise you end up pushing your train into itself.

I don't think that really matters. The physics of the combination means that small variations in the power of the motors balance out.

There is a theoretical midpoint where the train is being equally pulled and pushed. This point shifts constantly depending on what the front and back of the train are doing.

For example when you enter a grade the front of the train has more work to do whilst the rear locomotive is on the flat and pushing carriages that are yet to enter the grade, hence the train compresses (you end up pushing the train into itself). As the front engine clears the rise the front loco has less work to do and the train stretches a little. On the flat the same thing happens with curves.

Of course when one of the locos runs low on power before the other, the good one ends up pushing or pulling the other until the drag of the dead loco becomes to much but you can minimise that by synchronising the battery changes.

:classic:

Edited February 13, 2011 by AussieJimbo

[pinioncorp]

I prefer to have my motors together. That way the motors always have around about the same amount of strain on them. It is also easier to connect them to the same battery source, or at least the same IR receiver. For 9V motors, it matters less, but I like to think that it keeps the train more balanced having the motors up the front, so they are always pulling a load. In my experience, there is less strain having a train moving forward than reverse pushing up on the load. Some of my carriages (namely the EN carriages) don't take being pushed too well, as they can't make a corner without derailing. The extra slack is needed in the couplers to space them enough to make a standard turn.

Running one motor faster then the other will do neither of them any good, regardless of where they are in the consist.

[AussieJimbo]

I can only go on my experience and this is possibly influenced by the regular need to climb grades in my floor layouts (I've got a rug that is 2 bricks high, I know the Lego dimensions of my furnishings. LOL. )

The worst thing in my view for motors is to have them struggling or wheel spinning. My passenger trains just run better with the front and rear locomotives, which is a real world configuration anyway for similar reasons. The EN is a different case, it doesn't really need help as long as it has traction.

You do have to be aware that you want the motors running at about the same speed so you try to make sure both IR receivers are visible when changing speed but that's pretty easy to do most of the time. As long as you aren't wheel spinning the motors are running at the same speed even if one is a setting or two different. In that case that motor is effectively just doing more work which is the equivalent of it pulling a heavier train on it's own.

When hauling super-long freight trains a helper engine at the rear is almost essential as often half of the train can still be the other side of a curved section and will just pull itself off the track no matter how much power you have at the front.

Each to their own but I'm a firm believer in the the front and back configuration, especially for the passenger trains which are built like that in real life.

:classic:

Edited February 13, 2011 by AussieJimbo

[Buffalo]

With my 9V motors, I will put 2 in a locomotive and connect them together with a wire. That way if one of them loses power from the rails it will get power from the other motor. Even if my rails are dirty (which they usually are) the train runs perfectly.