Maximum distance apart large train wheels

[garethjellis]

Sorry if this has already been hashed out but...

what is the maximum wheel distance apart that we can go of fixed wheels without the train jumping tracks?

I am using the large flanged wheels as used in the Emerald Night.

thanks

[Duq]

On my BR 65 this is the distance:

BR65 Drivetrain by Duq, on Flickr

It kinda works but is not reliable. Ideally the flanged drivers should be closer. Unfortunately on this loco it would mean an enormous overhang.

[obsidianheart]

I dunno about maximums, but I can say from experience that the minimum is larger than this:

Tried it on a MOD, and the train wouldn't turn.

Edited February 15, 2014 by obsidianheart

[jtlan]

I dunno about maximums, but I can say from experience that the minimum is larger than this:

Tried it on a MOD, and the train wouldn't turn.

I don't see why that wouldn't work, plenty of models have the wheels set that close together.

@garethjellis: There's a distinction between maximum distance and distance at which scraping becomes unacceptable. I probably wouldn't do more than 10 or 11 studs axle-to-axle (i.e. measured between the centers of the axles).

[obsidianheart]

I don't see why that wouldn't work, plenty of models have the wheels set that close together.

I had to use one Flanged wheel and one unflanged to get it to work for me. Maybe I'm doing something wrong?

[Paperballpark]

I have Big Ben medium drivers spaced 13 apart, which works fine, although they're obviously smaller than the large drivers.

[dr_spock]

Is your engine a 0-6-0? It might work like that. If not, you can do flanged driver, flanged driver, blind driver configuration.

[ScotNick]

It really depends. 15 holes apart is possible in curves. The real problem are the switches. I just tried it out and it works fine with 10 holes in between, but I have the 9V switches, don't know with the newer ones as they changed something (if anything, it would work better).

[jtlan]

I had to use one Flanged wheel and one unflanged to get it to work for me. Maybe I'm doing something wrong?

Hmm. Were the connecting rods quartered properly? Were there other small wheels attached rigidly to the same frame somewhere else?

[Duq]

I dunno about maximums, but I can say from experience that the minimum is larger than this:

Tried it on a MOD, and the train wouldn't turn.

First of all you're hijacking someone elses post with your own question. Showing just this little detail of a train doesn't tell the whole story. If you want help getting this to work then you should start your own topic with a picture of the full train.

[obsidianheart]

First of all you're hijacking someone elses post with your own question. Showing just this little detail of a train doesn't tell the whole story. If you want help getting this to work then you should start your own topic with a picture of the full train.

Whoa. I wasn't trying to do that, I was just screwing around. That's why I didn't respond past the initial response to me. Anyway, I got it working a long time ago, so i'm not even asking a question. The "Maybe I'm doing something wrong?" was meant as rhetoric. Sorry I ruffled feathers.

[SavaTheAggie]

On my BR 65 this is the distance:

BR65 Drivetrain by Duq, on Flickr

It kinda works but is not reliable. Ideally the flanged drivers should be closer. Unfortunately on this loco it would mean an enormous overhang.

I built a 2-10-4 with this FBBF wheel spacing (or in my case BFBBF). Testing under ideal conditions went flawlessly, so I went forward and finished the train.

But running the locomotive on my ballasted track proved less successful - it started grinding in curves, so I had decided that the FBBF wheel spacing was too much. I abandoned the train to only be decorative, stripped out the motors, and went on my merry.

But now, some two years later, I discovered a flaw in my ballasted track, where the curves were resting on exposed studs, causing them to twist. I've since fixed the design but have not had a chance to revisit my 2-10-4.

It may be viable after all.

In any case I wouldn't suggest any larger spacing between flanged drivers - the FBBF spacing is pushing it.

--Tony

[Duq]

Hey Tony, my experience was similar; in lab conditions all seemed fine but real world at a show wasn't as reliable. Especially points can be tricky. I haven't had a chance to do some troubleshooting to try and improve the engine.

For the moment though I won't use FBBF again in a hurry. The problem of course for engines with 4 drivers is that the overhang at the front or back will be enormous. For my BR 55 I went for BFBF. I needed to keep the rear overhang to a minimum to keep it close to the tender but it means at the front it swings out 4 studs past the sleepers...

[legoman666]

If the axis of rotation is in the center of a FBBF config, then a BFFB would be almost the same as long as you kept the axis the same.

[Duq]

Legoman, I've absolutely no idea what you're trying to say... Can you explain, maybe with a picture?

[legoman666]

I'm trying to say that the amount of overhang on turns will not be very different between FBBF or BFFB as long as the wheel base is rigid to the chassis.

[Duq]

Ah, I didn't get the axis of rotation bit. FBBF or BFFB makes quite a difference in overhang. If the F wheels are further apart then more of the loco will be inside the curve and less will be outside. Don't have a picture handy to show the difference.

On top of that, you can't have BFFB at the wheel spacing shown above because you can't have the F drivers side by side.

[zephyr1934]

One thing with the FBBF on curves, if you were running on 9v track I bet you have better luck going clockwise than when you go counter clockwise. The rail connectors are not flush and provide an opportunity to climb the rails when the outside rail is on the right hand side, but no problem when the outside rail is on the left hand side.

On my BR 65 this is the distance:

BR65 Drivetrain by Duq, on Flickr

It kinda works but is not reliable. Ideally the flanged drivers should be closer. Unfortunately on this loco it would mean an enormous overhang.

That is just a brilliant little drive train, from the compact gear box to the axle connectors to deal with the otherwise non-integer axle spacings