Let’s talk about standard train wheels...

[Legotrainfan1996]

So, I’m fairly new to the LEGO Train scene and after playing around with some stock LEGO train sets (60051 and 60052) I decided to branch out and make some of my own MOCs. Lately I’ve been having some trouble with the stock train wheels that come with most rolling stock. I’ve always been fascinated by German locomotives and rolling stock, so that’s what I’ve loosely based these on, but the 2 wheel carriages just don’t want to take the turns :(  They are 14 studs apart (like the cattle car in set 60052) so I’m not entirely sure what the issue is. Any suggestions? 

Edited April 3, 2018 by Legotrainfan1996

[sed6]

The wheel centers on the cattle car are only 12 studs, not 14. 12 is the max you can run with SINGLE axles. With double axles on each end you MUST pivot the truck to prevent binding around a curve. See my post here for more info. Good luck!

[Legotrainfan1996]

11 minutes ago, sed6 said:

only 12 studs, not 14

Ok, I was actually counting from the ends of the trucks, my mistake XD but if we are talking about from right under the axle, it is 12 studs. After further investigation, the friction seems to be intensified by the fact that I have 3 cars with the same wheel length. Perhaps weight is an issue? The cattle car from 60052 is fairly light and even though the wheels are at 12, the car actually extends to 20,  so maybe that’s why the friction is greater? I wish I could post a picture, but for some reason, my phone says the file is too big.

Edited April 3, 2018 by Legotrainfan1996

[sed6]

So the length of the cars doesn't matter, nor the number of cars. You should be able to flick your car with a finger and it should roll all the way around a curve with no binding. If not you have a problem and it sounds like axle or truck placement. Again if you have two axles on each end it won't work unless the trucks (the two axles joined together) pivot as a unit. Both trucks must pivot, you can't pivot just one. As for pictures, this site doesn't allow you to post pictures of any real size. You should upload them to a file hosting service like Flickr (most here us that) and then embed a link to the picture.

[Legotrainfan1996]

Links to the actual cars in question

Pardon the mess. Unfortunately my wife doesn’t give me much room to work with.

Edited April 3, 2018 by Legotrainfan1996

[sed6]

Good pics. Nice MOC's! Hmm, perhaps the length, specifically the overhang at the end is causing a problem. First test each car individually, give them the flick test I mention above. Does each roll freely? If not check for binding in each wheel axle. Also check to see if the bumpers are touching, if so that can cause binding between the wheels and rails. See my pic below; with just one stud between the wheels and coupler there's lots of room between the bumpers, with two studs the distance is reduced, with three studs the bumpers are now touching. With three studs, at least in my test platform, the cars still roll smoothly. Four studs though cause enough binding to prevent smooth rolling. When I coupled them together with four stud spacing I immediately felt the cars shift, they tried to 'straighten' themselves out causing binding between the wheels and rails. As best I can tell from your pics you look to have just three studs between your wheels and couplers, so I'd think you'd be okay.  You're gonna have to play with them some more to figure it out.  

 

[Hod Carrier]

It is possible to go longer, even with a larger overhang at the car ends, if you allow the axles to articulate. A few of us did some investigations about just this sort of problem earlier this year (click).

However, looking at your models I would estimate that the problem is not to length of the wheelbase (the distance between the axles) but, as @sed6 suggests, the buffers are interfering with the way in which each car moves relative to it's neighbour.

[Legotrainfan1996]

Alright, so I created a skeleton frame and played around with the cars for a bit and this is what I found: the lighter the car, the less friction I got. No matter what wheel configuration I used and how far the buffers were from each other, I still got the same rubbing I had before. You can see the real difference the weight of each car makes in this video

I also debunked the idea about the buffers based on what was said earlier and this

 

What I did see that didn’t make much sense was when the first car was entering the turn and the second was on a straight. This is what happened 

 

Any suggestions?

[sed6]

You video results don't surprise me. You're not fighting rolling resistance going around the corner as much as you are fighting the rub between the wheel flange and the rail. Heavier just makes for more resistance. I bet if you move your axles closer, space them 10 studs, the problem will be eliminated.

As for your last pic, that's part of your problem I suspect also. Your green car is trying to swing to the outside, thereby allowing the wheels to follow the curve and roll more freely while your flat car is trying to keep the green car straight in line. This is likely causing additional rub between the wheels on the green car and the rail. This just compounds your problem. 

If you don't want to move the wheels closer together your only other solution would be to join the couplers to the wheels (and the stairs) and pivot the whole unit. You can use a simple 2x2 turntable. Here's a pic of what I do. I use it this on all my cars and it works like a charm. 

 

Edited April 4, 2018 by sed6
cnat spele

[Hod Carrier]

I agree. Weight is simply magnifying the problem you already have, which is that the wheels are binding against the rails creating unwanted friction. At @12 studs between each axle your car is quite long to be using fixed axles like this. If you have too many cars of this type in a train or your loco is not sufficiently powerful to overcome the friction you will find that it starts to become a problem. A single lightweight car like the cattle car in set 60051 would be fine, but you're talking about an entire train. Each car you add to the train multiplies the amount of friction experienced.

If you don't want to use bogies you will need to explore methods of axle articulation, such as was used in the thread I linked to yesterday.

That last photo shouldn't be anything to worry about. It's simply the swing due to the length of the overhang at the end of each car. Yes, each car is trying to pull the other slightly to the side, but it's not adding too much additional friction and the articulation on the magnets is sufficient to deal with this. If you set up almost any train onto a bend like this you will see a similar twisting of the coupling magnets.

[Legotrainfan1996]

Thank you both for your input. Unfortunately, I’ve been tied up between work and gathering pieces for what I hope will be a worthy solution. Pictures to come soon!

[Legotrainfan1996]

Finally, I’ve produced a solution, more along the lines of Sed6’s last post. Here’s the final result:

A close up of the boggie attached

and a shot of what it looks like by itself

They work really well when being pulled, but they do suffer from binding if they are being pushed. Many thanks to the both of you. Of course, this last post wouldn’t be complete without running the cars, so here you are! 

 

Edited April 14, 2018 by Legotrainfan1996