12 wheel to 8 wheel loco change?

[PrairieTrains]

Pardon me if this is a dumb question. I have purchased (without being aware of all the problems I would have) three 12 wheel locos. No matter what I do - they simply will not traverse my track configurations. I know that some of my curves are too tight. The eight wheel locos do OK. Can you change out the pick up wheels from 12 to 8? If so, where is the best source of such wheels - these are PROTO 2000 units from Walthers. Thank you for your advice. I may just have to display them somewhere in an engine warehouse!

[e-paw]

I guess that these are 6 axle desales. You could always remove the center axle on each truck, or grind down the flanges of the center axles. If you think big... you could tear down and rebuild your layout with bigger curves?

[yellowlynn]

Without knowing style loco or track radius, I can only throw out a possibility. Is it possible that the trucks are not able to turn enough to follow the curve? Sometimes they bind, or catch on the coupler or frame causing it to derail. I have some 6 axle diesels that jump because of that, and that is on a really tight radius, about 15-17".

Lynn

[jeffrey-wimberl]

I run Proto 2000 12 wheel locos on 18" radius. Most don't cause a problem but on some I have no choice but to remove the center wheelset from each truck. On the E series (E6 and E7 in my case) it requires that the wheelset be removed, the wheels removed from the axle gear and the axle gear placed back into the truck.

[Russ Bellinis]

I think it depends on what loco you have as to the radius it will handle. Most of the first and second generation units up through Sd45-2 will handle an 18 inch radius. The modern power units like Sd75 and newer, GE -8 C types etc. are so big that Atlas is now making Snap Track in 24 or 26 inch radius (I can't remember which) to accommodate large modern power.

[green_elite_cab]

Originally Posted by PrairieTrains

Pardon me if this is a dumb question. I have purchased (without being aware of all the problems I would have) three 12 wheel locos. No matter what I do - they simply will not traverse my track configurations. I know that some of my curves are too tight. The eight wheel locos do OK. Can you change out the pick up wheels from 12 to 8? If so, where is the best source of such wheels - these are PROTO 2000 units from Walthers. Thank you for your advice. I may just have to display them somewhere in an engine warehouse!

To be honest with you, i really think you are misinterpreting your problem.

Its not the locomotives you should be concerned about, its your track. As others have mentioned, many 6 axle locomotives will still run through 18"r curves. I've even played with a AC4400CW and got it to run. If you have anything tighter than that, then i can see where your problem is.

That said, IF you have well put together trackwork, these problems should be at a minimum. At the very worst case scenario, your locomotive will have to much overhang and pull the train off the rails, and then removing wheel sets won't help you.

In the end, the layout will frustrate you if you don't fix the track.

You should also get a track guage to make sure that everything is in guage, and that none of your track is warped, because that will cause trouble to. Make sure all your track is aligned, because if there are kinks or gaps this can also cause derailments, and removing a wheel will not solve it.

You should check to make sure none of your track configurations include "S" curves, or other really bad shapes. An S curve might be alright for a crossover, (however, AVOID snap switches), but if you have any situations like that, remove them. Another way to help going into curves is to had an easement.

I really think its your track, not your locomotives. If it isn't to late, i'd suggest tearing out your tracks and re-laying a new track plan that is more so compatible with the equipment you want to run. Otherwise the hobby will become frustrating, and it will be impossible to run the trains you want to run.

At the very least, find these "track configurations" that cause trouble, and eliminate them. Replace them with a greater radius, or a straighter route.

Originally Posted by Russ Bellinis

I think it depends on what loco you have as to the radius it will handle. Most of the first and second generation units up through Sd45-2 will handle an 18 inch radius. The modern power units like Sd75 and newer, GE -8 C types etc. are so big that Atlas is now making Snap Track in 24 or 26 inch radius (I can't remember which) to accommodate large modern power.

I've coaxed an AC4400CW onto 18" curves, but my SD45-2 still pulls the train off the rails. the regular SD45 seems to be about right though.

I think its code 83 track that they made into 24. I wouldn't be surprised if both are available now.

[ed acosta]

Well, the problem seems to be rather vague and so the possible answers appear to be heading in all directions. Taken the given information, there is a strong likelihood that six wheel trucks will track on 18" radius. What we don't know is whether the track is correctly gauged or whether there are uneven spots that would cause a wheel to lift off the rail.

Lets focus on the loco. Turning the loco upside-down, rotate the trucks left or right, as if the loco were negotiating an 18" radius turn. Do you notice if the trucks are obstructed (cast-on tanks, steps, etc.)? Now, do the same while rolling the trucks up and down slightly simulating uneven track. Is there sufficient motion with the trucks to enable them to stay on the track?

Your problem statement does not tell us if the loco is coupled to anything when it derails. If so, perhaps there is not enough swing in the coupler shank, or perhaps the coupler shanks are too short causing the end steps of one loco to knock the other one.

Now for the last test: run the loco through your trackwork as slow as you possibly can all the way to where if first derails. Run it again until you can actually see whether a wheel is lifting, or a truck is unable to rotate sufficiently, or whether the coupler is the problem. Roll to the next problem spot and then the next to determine if the same situation reoccurs.

With some fussing and some filing, you may get the loco to negotiate nearly any track situation. However, it is up to you to decide whether to isolate and fix the problem track or keep on modifying locos. Its your call!

[Russ Bellinis]

I think your problem will be either in the track or an interference problem with the locomotive. The answer will not be to make 3 axle trucks into 2 axle trucks. A couple of years ago I wrote an article for the "Tips &Tricks" section of the Gauge titled "My train derails at..." I intended it to be a comprehensive guide on how to isolate and fix problems that cause a train to derail. Since I switched from Internet Explorer to Firefox, I have not been able to post a link without opening I.E. and doing my posting there. I did go to the "Tips and Tricks" forum in the reference section of the Gauge and bumped the thread to the top of the page. You might be able to find some helpful information there to isolate your problem.

[MasonJar]

Here's Russ' link:

http://www.zealot.com/forum/showthread.php?t=115011

It is a great article and covers virtually every aspect of troubleshooting derailments, from the loco or car itself, to track problems, to a few other tips you might not think of...

One other "fix" you might consider if the 6 axels really are the problem is "blind" wheels - that is wheels with no flange. They can move freely back and forth over the rail as required, maintaining appearance, but not interfering. NWSL is one possible source for these parts.

Andrew