edsmith0075

Custom PF rail trucks, how to question...

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Greetings everyone, I have caught the lego train bug and in my expansion I would like to use steam engines such as the emerald night on my setups. So here is my idea, I would like to make either a boxcar or match Emerald night rail car that can house two small pf motors to drive the train. I have come across some great gearing designs but I am stuck on how to attach the custom geared trucks to the frame of the train car. With the lego brand PF train motors they have that tab on the top to allow pivoting and mounting. How would that work with a custom geared setup? Any advice is appreciated and I am grateful for the wealth of knowledge this community has to offer.

Ed

http://www.flickr.com/photos/edsmith0075/

My flickr account has alot of my lego trains and other lego projects

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Couldnt you just use the loco to power the train? The EN was designed to be used with a PF motor in the cab.

And to answer the question, a PF train bogie motor has all the gearing in the bogie itself. But if you want to use XL motors with gearing for the bogies, The vertical drive axle acts as the pivot in MOST if not all designs. I dont understand your question entirely, so if what Im saying doesnt help at all, Im sorry.

Oh, and your link to the flickr page doesnt work. It would help if you had some pictures of the issue you are having as your description is a bit hard to follow.

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spitfire, you are correct. I apologize for the confusion and the bad link. Let me restart...

My emerald night is currently powered with the XL motor but the train struggles on the track in some places such as switches or grade variants in the track. The wheels just slip if the track is uneven in any way. Being that this setup is currently on the carpet in my house dips and rises are common and often prevent the EN from being able to run smoothly. My idea is to place a boxcar or EN passenger car equipped with PF motors behind the coal tender. In doing so the idea wiil be to help push the engine over areas where it may slip and ensure a smoother ride.

http://www.flickr.com/photos/edsmith0075/sets

Hopefully , the above link works better...

The pivot point that you mention is what I need help under standing. The PF boogies are attached to the base with the clip on the top that fits into a hole. How would this work on a boogie that I build myself with gears to be powered by a motor mounted on the bases?

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I'm assuming you're using the standard train baseplate and E- or M-motors: The motors attach directly to the base with pins (vertically), and like Spitfire2865 said, the drive axle works as the pivot. It'll be problematic once the train starts to get heavy, though, as the rotational force of the motor can twist the bogie of the rails if there isn't enough weight keeping the car on the rails in the first place.

That said, the basic PF-train motor should do the job just fine, without looking too much out of place. The Emerald Night can be motorized also, altough it is recommended that you modify it to cope with the power and to reduce some of the friction problems it has.

Edit: This was posted right after the reply above! So I guess you can ignore that last bit. :laugh:

Edited by Freddie

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Railbricks a free online magazine ( http://railbricks.com ) issue number 5 has instructions for a tender with geared trucks. You should be able to adapt it to your application.

Bill

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My emerald night is currently powered with the XL motor but the train struggles on the track in some places such as switches or grade variants in the track. The wheels just slip if the track is uneven in any way. Being that this setup is currently on the carpet in my house dips and rises are common and often prevent the EN from being able to run smoothly. My idea is to place a boxcar or EN passenger car equipped with PF motors behind the coal tender. In doing so the idea wiil be to help push the engine over areas where it may slip and ensure a smoother ride.

The EN was designed to run on flat surfaces. Lego didn't anticipate things like carpet in the design, but that was nothing new, it is just the most pronounced with the EN. The cause is simple enough, if the three sets of wheels are in a rigid plane and it goes over a dip, of course the end wheels will lift the middle wheels right off the track. Too bad the middle wheels are the power. One thing that you can do is to add joints to allow the front and rear trucks to also bend up/down, thus allowing the middle drive wheels to better follow the track. I did that on mine but I don't think I have any pictures showing it in action. If you do this, you may also need to carve out a plate worth of space (so that the leading and trailing trucks have somewhere to go when the middle driving wheels drop down in a dip.

It can be VERY challenging to work out a structure that is reliable enough, strong enough, and attractive enough to do the job under a steam engine. If you are thinking of heading that way, you definitely want to build prototypes of the frame/running gear to make sure everything functions before you jump headlong into building or rebuilding the rest of the model.

So your intuition is good, bypass the problem with the EN drive train and put the motor on a two truck car. The Railbricks tip above is probably the easiest resource to follow, but you don't need to do the complicated gearing proposed in that article. You could simply mount one motor on each truck using a technic axle both for the center pin and for propulsion. The PF train motor is an even simpler solution though. You can run two off of a single IR output, as I did with my very heavy superliners in Railbricks #10. In particular, see the bottom right photo on p42, where I bring the power wire out on the coupler side of one of the motors (thus eliminating the need for a polarity switch when running two motors under one PF engine). The front truck on this locomotive is also a PF motor, but the wire comes out away from the coupler on that motor, and enters the body in a more conventional fashion.

At any rate, if you move the motor out of the EN, you might want to also pull all of the gearing out too (it adds a lot of drag and will not serve any purpose without the motor.

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Thanks to everyone for their incredible guidance and feedback. It sounds like the technic rod acts as the pin for the boogie and that is what I was really trying to understand. Railbricks is an awesome resource! Thanks again and I can't wait to start my new project, I will post pics as it goes.

Also, one of the other reasons I need this to work is because I am looking to build a garden railroad out of lego gauge trains and it will have switches, dips and lulls.

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Thanks to everyone for their incredible guidance and feedback. It sounds like the technic rod acts as the pin for the boogie and that is what I was really trying to understand. Railbricks is an awesome resource! Thanks again and I can't wait to start my new project, I will post pics as it goes.

Also, one of the other reasons I need this to work is because I am looking to build a garden railroad out of lego gauge trains and it will have switches, dips and lulls.

I would suggest you dont do Lego outside. There was an article here about that a while ago by Locomotive Annie I think. Well, if you are dead set on doing lego outdoors, you will want to find an alternative track system rather than the Lego brand track. Sunlight does horrible things to Lego.

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I would suggest you dont do Lego outside. There was an article here about that a while ago by Locomotive Annie I think. Well, if you are dead set on doing lego outdoors, you will want to find an alternative track system rather than the Lego brand track. Sunlight does horrible things to Lego.

Although I've never tried it, everything I've heard is that ABS hates prolonged sunlight. Here's one possible alternative to Lego track (and a lot cheaper too). Scroll down for discussion about alternatives for outdoor use

PS, speaking of which, someone just bumped the garden railway thread.

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