Looking for help with my steam train

[jonwil]

I have a steam train that I have built but which doesn't seem to run properly on the track.

I have created an LDD file of the mechanical parts of the train. Above that is just decorative.

https://drive.google.com/file/d/1S5foUIlzxhQXCWPLFN2vMf30_wI61Bec/view?usp=sharing

The train has trouble making it around the track and I can see some white-ish marks on the black axles holding the driving wheels on (at the point they pass through the grey bricks). The red rubber belts on the drivers have turned a dark grey color.

Anyone have any idea on how to get my train moving better?

[ColletArrow]

This is a mystery; if you've got the train built exactly as in the LDD file, it should run easily. What do you mean when you say it doesn't "run properly"? Is the motor spinning and slipping, or stalling? Is the train keeping to the track, or derailing?

If the motor is spinning, the only suggestion I can make is to lighten the engine and put more weight above the 9V train motor in the tender. The Boat Weight brick 73090 would probably be good if you have any; alternatively, anything metal (nuts, bolts, screws etc) above the motor should help. Otherwise, I'm not really sure. A video or even just some pictures of exactly what the problem is might help.

The white dust on LEGO axles is common. If you want to see some really bad build-ups, have a look at some GBC (Great Ball Contraptions); mechanical LEGO models running for 2 days or more continuously can produce interesting results.

[sed6]

Agree with the above, posting some pics or a video would help.

[jonwil]

I dont know exactly what's going wrong, I know the guys at the last train show told me they tried to run my train but it wasn't working so well. I think they were able to get it running at least partially by sticking a heavy weight (some kind of 3rd party programmable brick IIRC) on top of the train motor in the otherwise empty tender as well as removing the connecting rods from the wheels (which makes it look not so nice). I didn't actually see it running at the times I was there so I dont know for sure how well it ran.

Adding more weight over the motor is definitely a good idea, I have one of those black weight bricks somewhere and will use it. I will also fiddle with the connecting rod design (since removing them seemed to help matters).

Pushing it around corners (I dont have a setup I can use to run it under power) it does seem to get hung up a little bit, is there anything in the design that might cause that?

 

[JEB314 (James)]

Hi @jonwil,

I run an Emerald Night with a 9v motor under the tender and had some problems with that to begin with.

As has already been mentioned, the best piece of advice for all tender driven locos is adequate weight!

I suggest anywhere between 2 and 4 boat weights worth of weight to gain better traction. (I used 4 for EN!)

As for the connecting rods and motion in general, definitely have a play around and experiment with angles, heights and distances within parameters that you feel don't too drastically effect the look of the model!

Another thought, have you considered slight lubrication around the black axles through the grey bricks? Some people are very much against it, but it can help in the right circumstances to reduce friction.

Hope that helps! 

[sed6]

I took a look at your design and I think the problem is with your front truck. There isn't sufficient pivot of the first four wheels. Your 2x2 modified plates with the technic pin serving as a pivot are too close together. Try spacing them apart one or two or three studs. That front truck needs a double pivot point to go around curves properly. While your design is technically a double pivot, the 2x2 modified plates are touching, or so close to touching, as to simply count as a single pivot point. And a poor one at that, because of their design they cannot pivot all that much, maybe 30 degrees off center, which would be okay if you had only a single axle immediately behind it. But you don't, you have three axles behind it so that front truck needs to not only pivot more than 30 degrees, it also needs to be able to move off the centerline as it does so, hence the need for an effective double pivot point.  Make sense?

Edited May 24, 2018 by sed6

[jonwil]

I added weight to the tender, I lengthened the boiler and front of the train by one stud, I moved the cylinders forward one stud, I adjusted the connecting rods so the axle still went through the cylinders and I replaced the 2 hole beam with a 3 hole beam to give the front truck more movement. Hopefully those fixes will make it work better.

 

[sed6]

Awesome! Keep us posted!

On 5/20/2018 at 6:03 PM, jonwil said:

Pushing it around corners (I dont have a setup I can use to run it under power) it does seem to get hung up a little bit, is there anything in the design that might cause that?

Do you not have track to run it on?

[jonwil]

Right now all I have set up is the section of track that is part of my contribution to the layout. I have other bits of 9v track as well but I dont currently have a working speed controller (the insulation on my sets of track connecting wires has perished) so I have no way to test how it runs under power until the next show in a couple weeks.

 

[sed6]

I understand. The good news is you can simply push your train around to get a good idea of how it will run. Binding of parts, like the front truck going around corners, will be pretty easy to spot. Push from behind the tender, not on top of the locomotive. Holding the locomotive with your hand will add weight and false traction which will mask problems. That said, I would think a couple of wires would be easy to fix!

[Gioppa]

i see another problem:

Sorry for my english, but i'm italian and i hope i can explain it vewry well.

you have the same problem have the original Emerald Night

The rods have to be in line with the center of the big weels, like the in the Emerald that one go forw-back is not in line with the center of the wheels.

Very easy; when i fix that on my Emerald, it run for one day and the only problem is the low battery.