Best option to upgrade the Pilot on an AHM/Mehano GP18

Model Railroader General Discussion (Model Railroader)
1

I have 2 of these beasts that I got for $6 total. Neither runs, but I can get these working agian in my sleep. May even swap in some cheap can motors to improve them. I plan to strip them, rip off the handrails, replace the fans with appropriate ones plus add better handrails and wire steps and paint in my club’s scheme. But the single biggest failing on this locomotive is the pilots and steps. Open pilot is easy to fill, but the steps are also wrong.

Anyone ever fixed this on these? Precision makes an early EMD pilot with steps that seems like a decent price and will work well, but wondering if I’m missing an obvious solution.

I don’t have anything in my parts bin to help either. Otherwise this would be relativley easy.

2

I think you need to think this through. Are the couplers or coupler boxes attached to the pilot? If so how would you fasten couplers to a glued on pilot? Best choice may be a coupleof sacrificial shells with better degree of accuracy pilots. I would start with some Athearn blue box shells.

3

Someone did suggest to me to look at sacrificial shells. The problem with the Athearn is that it’s still not a great pilot, because of the section missing to get the couple on chassis on and I’d then also be committing to a new drive line since the Mehano walkway and pilot are part of the plastic frame with motor and truck mounting. The Atlas Classic GP7/9 frame/Pilot could work and costs about the same as the Precision parts, but again, I’d have to move over to different trucks to make that work and I’m not sure I’m willing to spend that much.

4

The photo below shows Athearn diesels with body-mounted couplers and closed-in pilots…

This photo is a little clearer, and will enlarge if clicked-upon…

If you’re interested, I can take some photos to show how it’s done, as it’s not difficult.

Wayne

5

I know how to close in the pilots. But that’s added work and a lot more cost because, again, I’m now ditching a much larger portion of the GP18…Now, the AHM shell is still better than the Athearn shell, so it would still be a better loco, but it would still cost significantly more money.

So I guess I’ll modify my original question, is there a better option than the Precision pilot and steps that won’t turn a $12 project into a $50 project.

6

I would watch eBay for a clunker GP18 with the pilot you want and go for it. A GP18 is a GP18, simply chop off and replace the portion you need. Simple kitbash.

Edit:

If your GP18 is a Rivarossi, all the Rivarossi diesel drives I’ve seen are the pits. Single rear truck powered and terrible power pickup. I kitbashed a pair of Athearn PA frames and fit two Rivarossi Krauss Maffei ML-4000 shells on them, from two axle drive and four axle power pickup to all wheel drive and power pickup.

Mel

Modeling the early to mid 1950s SP in HO scale since 1951

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

Aging is not for wimps.

7

Rivarossi never made a GP18. Mehano made the GP18 for multiple Manufacturers including AHM, IHC and Bachmann. AHM version is 8 wheel drive 4 wheel pickup just like the other Mehano 4 wheel diesels. The Bachmann version is 8 wheel pickup so even better. If I had a Proto 2000 shell lying around, I would be using that as the basis for these, not the Mehano.

8

I don’t quite follow why you would need to change the trucks to use the Precision parts or Atlas pilot. The structural part of the Mehano frame doesn’t go all the way to the pilots, it stops right past the hood mounting clips which are beyond the truck mounts. If you made a slightly angled cut right at the inside edge of the steps so they meet at a v just beyond the hood mounting hole, I think you should be able to remove them and the pilots and graft on a new section without affecting the chassis fit or rigidity. The sill thickness might not match though.

Or, are the trucls

9

Hardly extra work to close-in the pilots and add body-mounted couplers, and if you’ve got sheet styrene on-hand, even as saved scraps, there is no “cost” involved.

I “get” the idea of improving a model that doesn’t quite meet your needs, but we might have a better chance of being useful if you’d show us a picture of what you have, and your thoughts on what you think needs to be added or removed or altered.

I happened to stumble across this a few minutes ago. While it may be pricier than your current plan, it might be a better option in the long run.

Wayne

10

The initial suggestion was that the Precision part would not offer sufficient structural integrity to handle body mount couplers, because of the joint with the frame and so I should look at a complete solution such as the Athearn pilot+ walkways. So I was responding to that comment. I’m not sure that’s true, but I will take the advice given as worthy of consideration. That’s what lead me down this path. Cutting the Athearn BB GP7/9 body off leaving the steps and pilots isn’t really sufficient to the need. The Atlas Classic GP7/9 frame appears to be the closest design. I guess the real thing I’m trying to figure out is if there’s a different product or different way to attach this that is either less expensive, or the same cost, but “better” where better could mean, more robust, easier to do, etc. But that is certainly not significantly more expensive.

With the Precision part being the baseline.

11

I guess I made a bad assumption that the old heads here knew what an AHM GP 18 looked like without needing pictures. It’s been a part of the hobby for at least 45 years now. I’m well a

12

I agree with Wayne. My dad had a couple of these 40 years ago, and we used styrene to close the pilots and body mounted the couplers. I remember it being easy to, so why complicate things?

13

You have $6.00 invested and want to make a poor model into a good model for little cost. You are going to have to invest close to the cost of a good model in a poor model. Why not just put the money into a better model and save the time and effort for something else.

14

I think any part grafted on should be strong enough for body mounted couplers, especially with a little reinforcement. The forces aren’t that great, and they would be spread out over a wide joint.

15

“In my first post, I said the Pilot is open for truck mounted couplers and that was an easy fix, but that the steps are also not accurate and are sufficiently inaccurate that I want to put in the effort to address them. couplers and that was an easy fix, but that the steps are also not accurate and are sufficiently inaccurate that I want to put in the effort to address them.”

So you’re willing to fill in the AMT pilot yourself? It seems to me from your quote that all you need or want to do is make the steps more accurate. You can cut them off and do one of three things.

  1. You can scratch build the stairs. This is the cheapest option and the outcome relies on your modeling skill. If you do choose this option, consider using bread clips for the material. They are made from a thin, sturdy plastic and are in every home. I often use them for step repair.

  2. You can have the steps 3-D modeled. Do a search on Shapeways and other printing sites to see if any have already been created. If not, draw up some yourself or hire someone.

  3. Purchase a shell with more accurate steps and graft them on to your shell.

None of the options presented require removal of the pilot, or lessening the integrity of the front of the shell.

Do you plan to replace the oversized railings, or do those inaccuracies not bother you?

16

Cannon and Company and Plano make etched pieces for steps. Etched parts look killer. Combining styrene and etched parts should give you the look you want.

17

The reason I considered taking the whole pilot off is becaus

18

I don’t think this is true at all. Though it does depend on your definition of a good model. I’m not planning to make this as accurate as the afformentioned Genesis. However, I do believe that I can make this into an extremely credible model and a great runner for around $20 in detail parts including the pilots should I go that route.

I can get the unit running again with the existing motor, Or drop in a nice modern motor for less than $5 and get a smooth quiet locomotive.

The only additional cost then would be DCC and that price is really up to whether I decide to add sound.

19

Thanks for the link to those photos. They explain some of your concerns, but after viewing those pictures, I would respectfully consider your proposed “upgrades” to be both a waste of time and waste of money, too, even if the cost of those parts is reasonable.

Many years ago, I bought a pair of LifeLike RS-11s via mail order (sight unseen), mainly because I liked the look of the real RS-11s. That was in the days before the release of the Proto-2000 locos, but when the latter appeared, I dubbed my mail-order locos as Proto-no-thousands.

They had similar open pilots, with truck-mounted couplers, one powered truck that ran like a dead snail, and handrails fat enough to be train rails.

I replaced them with a pair of RS-11s from Atlas, but rather than scrap the sow’s ears, I decided to see if I could salvage something from them, not necessarily into a silk purse, but maybe a decent change wallet.

Here’s one of the Atlas locos (with what now would be considered too-thick handrails)…

…and one of the de-motored and reworked Proto-no-thousand locos…

When I backdated my layout’s era, most of the diesels had to go, but I had no trouble finding buyers, even for the two dummy units, each of which went with one of the Atlas units.

If you want a good-looking and decent running GP18, look for one on-line, as LifeLike’s Proto2000 GP18s look great, and even if the one you buy has the split gear issue, it’s easy enough to fix for not much money.

You can check 'em out HERE

20

“The joy is in the journey, the struggle is part of the joy and the final destination is not an end but another beginning of another journey.”

Again, My goal is to spend $20 and to experience the specific hobby activities involved in turning this into a functioning locomotive with details I find acceptable and that is sufficiently reliable in DC that I am willing to add DCC to it whether that means a $15 motor only or a $59 basic sound unit.

Purchasing a GP18, which, looking on EBAY is going to be at least $50 once shipping is included is not the same hobby activity. Examples of the work involved in a single truck drive unit are useful, but not an entirely fair comparison as this is again, an 8 wheel drive unit with a reasonable motor.

Again, and this seems to happen time and again on hobby forums, It may not be fathomable to everyone, but some people derive specific joy from doing this kind of thing.

I mean, I don’t need a GP18, If I didn’t have these units, I wouldn’t be interested in this at all, but I do have the units and I want to work on the skills and so, I’m seeking advice on the methods.

Anyway, as I said some posts up, while the original motor could be used with DCC, it’s not as good as a modern one, so I just paid $17 including shipping to get 8 new Iragashi 5 pole DC motors. Based on some advice I got from the RepowerAndRegear group. It’s Aliexpress, so who knows when it arrives, but at about $2 each (including shipping), it’s going to be a huge performance upgrade.