Gearing a XL or M Motor for a LEGO MOC Train

[Tearloch]

I am looking at creating my first ground up MOC train of a 1970's era Burlington Northern passenger train (EMD E9). I am starting with the front end of the Santa Fe Super Chief as a guide, but the overall length of this MOC will be about 40 studs based on scaling (consistent with Super Chief, BNSF, and Maerk). This MOC will include 3 axle trucks, so I am forced to delve into the world of using a XL or M motor, and gearing it to run well. I have seen several other topics that mention this, but I am looking for advice on specific technic gear setups to make either of these motors operate with similar power and speed as the new PF train motors (or the old 9V motors).

Links to articles would be great. I plan to use the 3 axle truck design from one of the RailBrick issues (with the floating center axle).

I understand most people seem to mount the motor vertically, but has anyone tried to mount it horizontally (similar to the setup of the Emerald Night)? What are the pros and cons of mounting the motor vertically or horizontally?

Any help would be appreciated.

[Sokratesz]

If you mount the motor vertically, you only need two gears to get the torque to the wheels. Less gears = less resistance = more power.

XL motors are quite slow and for small-medium trains I've seen people gear them 1:1 to the wheels. For large trains it's usually 2:1 I think.

- Sok.

Edited December 6, 2011 by Sokratesz

[AndyC]

If you can fit them in a pair of 'knob gears' can transfer the power through 90 degrees with little loss and practically no chance of slippage.

Edited December 6, 2011 by AndyC

[LEGO Train 12 Volts]

Maybe this can help horizontal solution

Edited December 8, 2011 by LEGO Train 12 Volts

[clcwong]

Maybe this can help horizontal solution

Wooo....I love this design a lot

kind of remind me the train I got when I was small..

[Shupp]

I made a pair of E7s with Power Functions.

They're probably bigger than you want to go, but maybe the truck design will be helpful. I prefer vertical mounting of the motors because it usually involves fewer steps with the gears, and I find it holds together better. With the vertical arrangement you can just directly attach motors to the trucks and let them free float in the locomotive like in this example here:

[adrian_dixon]

Here is a link to a moc i am working on at the moment i am trying to fit 2 m motors inside the 5 wide body. I reckon i will have to put the battery and receiver in a container car or something.

http://www.brickshelf.com/cgi-bin/gallery.cgi?i=5290788

[Duq]

I'm working on a model that at the moment has two M-motors with a 20:12 gearing to the wheels. The model is 6-wide so I've no room for XL motors.

I've a steam engine with a single M-motor and 1:1 gearing to the large drivers. That runs ok so I figured with the smaller wheels I'd need to gear up for this new model. Thing is, it's fairly slow and had surprisingly little power when I tested it last weekend, even with a fully charged battery. Would 1:1 gearing be better?

[peterab]

I'm working on a model that at the moment has two M-motors with a 20:12 gearing to the wheels. The model is 6-wide so I've no room for XL motors.

I've a steam engine with a single M-motor and 1:1 gearing to the large drivers. That runs ok so I figured with the smaller wheels I'd need to gear up for this new model. Thing is, it's fairly slow and had surprisingly little power when I tested it last weekend, even with a fully charged battery. Would 1:1 gearing be better?

I use the same gearing for my BR 103, with two M motors, one on each bogie. That pulls a handful of 50 stud, 7-wide carriages quite well, though not overly fast. Is there any chance you've got a point of friction in the design? My bogie design (3 axels with centre on sliding) has gone through a number of iterations as it was flexing and coming apart under load. Before the problem became apparent the performance was pretty bad.

[Duq]

Mine are also 3-axle with sliding middle, based on the excellent design by Scruffulous. I didn't have room for a vertical mount so I've got two 90-degree gearings with the gearing up done inside the engine. The bogie gearing is 1:1 using 12t bevels.

I'll have a good look at the bogies to see where the friction may be.

[peterab]

Mine are also 3-axle with sliding middle, based on the excellent design by Scruffulous. I didn't have room for a vertical mount so I've got two 90-degree gearings with the gearing up done inside the engine. The bogie gearing is 1:1 using 12t bevels.

I'll have a good look at the bogies to see where the friction may be.

Do you have two 90 degree turns per bogie? That might be enough to cause problems.

In the development of my bogies, based on Scott Wardlaw's from Railbricks I found the bogie flexed alowing the cogs to slip. Mike's (Scruffulous) looks very similar to my earlier weak ones. I'll try and put up a better pick of my bogie in a few days. This weekend I'll be at an AMRA train show :-)

BTW it's odd that that's the first time I've seen Mikes bogie since he is in my LUG and train club. Instead of seeing it in person, you've linked to it from the other side of the world