Key/Samhongsa cab forwards

[ATSF_Ron]

Good evening, gents!

Does anyone have any first-hand experience with these particular cab forwards?  Either owning or working on any?  I know the Nakamura/Japan versions are better, but I have my eye on a couple earlier Samhongsa units (AC-6 and AC-7, I believe first run).  Mark/Spookshow gives these a "D" rating, which scares me.  The seller says the models run well and are in mint condition.  I have bought brass steam from this seller before with great results, so I trust him.  I'm just concerned about the issues Mark mentions in his web site.  I can deal with the funky stiff wire to drawbar connection and replace that with a small mini wire directly to the motor from the tender.  I have read on Mark's site and somewhere else that I can't recall, where the valve gear can be "bindy" on these.  Also the minimum radius Mark mentions is doable but maybe tight in a couple areas.  I use 16-19" radius on my mainline curves.  The bindy valve gear is above my pay grade to deal with, so that would probably be a dealbreaker!

One more thing, I'm not hesitant about tearing down locos.  I've had several steamers and diesels down to nuts and bolts, but never a brass loco.  I shudder to think of taking one of these beasts apart farther than what is required to give it a proper lube.    Any comments or advice on these would be greatly appreciated, thanks!

Ron

[u18b]

I don't own one of these nor tinkered with one.   But I do know Mark.   If he says these like wide curves of 19" and 19 is pushing it....

Then either he had a poor specimen to examine, or your 16 inch curves are going to cause problems.  I think you should take his warning seriously.

[peteski]

I don't own one of these nor tinkered with one.   But I do know Mark.   If he says these like wide curves of 19" and 19 is pushing it....

Then either he had a poor specimen to examine, or your 16 inch curves are going to cause problems.  I think you should take his warning seriously.

I was going to refer Ron to Spookshow's write-up, but he doesn't have one on this rare and expensive model.
http://spookshow.net/loco/keysam2882.html

[u18b]

I was going to refer Ron to Spookshow's write-up, but he doesn't have one on this rare and expensive model.
http://spookshow.net/loco/keysam2882.html

Yeah, Correct.  Mark posted recently asking anyone if they had the 2-8-8-2 Cab Forward he could review.   One has not appeared on traditional selling (that I have seen) for years.  It therefore makes sense that one big brass seller has a rating system.  One category is "Mythical" - meaning so few were made (and/or these are so desirable) that you hardly ever see one for sale.  The 2-8-8-2 definitely falls into that category.  Unfortunately for Mark, that also makes it pretty expensive.

But Ron was asking about other cab forwards- hence my answer.

[robert3985]

I haven't had any experience with Samhongsa Cab-Forwards, but I have had loads of experience with Samhongsa Big Boys, which have basically the same chassis as the Cab-Forwards.

That being said, I recently acquired a non-running, used Key Imports, Samhongsa built Big Boy with a broken U-joint mount and other problems after having been dropped (I assume from the type of damage).  Having fixed one of earlier Samhongsa Big Boys after it had been dropped at one of my LHS's, I was pretty certain I could fix it.

Yup, they're kind of a Chinese Puzzle to get apart and put back together, but it's mainly the rotating and sliding steam pipes near the smokebox that require three hands.

After I re-soldered the U-joint mount on the front engine and put the chassis back together and got the U-joint snapped together, my chassis ran, but quite "jerkily" as the valve pieces were binding.

Frankly, an N-scale steamer's valve gear isn't all that complicated and you can usually see where the various pieces are either misaligned (bent) or touching/rubbing against various other parts as everything goes round and round.

Took me about three adjustments to get the valve gear and connecting rods properly aligned and not touching/rubbing each other.

I got it all put back together and ran it on my 6' test module (two tracks 1.5" apart with a crossover made from a hand-made #6 turnout and a Micro Engineering #6, both with dead frogs and 10" section of track on one end that's a programming track which can be fully de-powered)...and it ran smooth as silk, starting from a bare creep, smoothly accelerating to what I think is a scale top speed without any jerkiness or intermittent stopping on the straight tracks.

However, as with many Samhongsa steam engines, I had problems with the tender picking up reliably when going through my test module's two dead-frog #6 turnouts, which is usually a problem at the engine's connecting bar with its two holes and funky soldered-on bronze spring contact wire, which bears against a matching NS pin on the tender, and/or the tender wheelsets not making consistent contact with their bearing journals. 

I cleaned the engine's connecting bar with a brass brush, a fine round file, 91% IPA and Bestine (Heptane) and discovered the springy bronze contact wire was loose...so I cleaned the cheap tin/lead solder off, and resoldered it with 96/4 Tin/Silver solder and cleaned the tender's matching NS pin with 91% IPA and Bestine.

This improved electrical pick-up to the point that it stalled on only one turnout, so I then cleaned the tender's wheelset "journals", which on the Big Boy are just brass fingers crimped over the axles of the Centipede Tender's wheelsets with my IPA/Bestine combination and I also cleaned any detritus off of the wheelsets' tires...and decided to add some weight to the inside of the tender.

This solved the electrical pickup problems, and the engine now runs smooth as silk through my test module.

What this long description is saying is that trouble-shooting these Samhongsa N-scale articulated steamers isn't all that difficult, especially if you're used to maintaining N-scale steam engines.

If your seller, with whom you've worked with before, says these run okay, then I would trust him.

On the other hand, your 16" to 19" mainline radii might be a problem...especially the 16" radius curves.  Since my mainlines are a 24" minimum radius (since I was planning on running Big Boys when designing my layout) I can't speak to the problems you might have with smaller mainline radii...but I would be cautious.  If your curves are smooth with no kinks, and your railheads are very level and where your rails are joined (soldered together I hope) are level and not kinked, you might not have functional problems down to a 16" radius...but 16" is really pushing it.  19" shouldn't be a problem except for appearance...but, once again, 16"???...for Cab-Forwards???  I wouldn't bet on a conventionally articulated N-scale steamer being able to reliably negotiate those.

The other problem that I've noticed, and why I don't run any brass Samhongsa Big Boys on my layout is their lack of pulling power.  My Key Big Boys will only pull about 18 cars...maybe 20...and my layout is designed for 30 car trains...which is why I sold all of my brass Big Boys and why I am selling this latest Key Big Boy, even though I love the conventional articulation's appearance when on curves and negotiating turnouts.

I doubt that the Samhongsa Cab-Forwards will pull much more than 20 cars (at the most) either, so...if you have visions of long trains behind them, they most likely aren't going to be up to it.

However, if you're getting a good price for them, you might consider re-selling them since they're bringing a pretty good price on eBay since they're rare, and most brass collectors don't care if they run well or not.

It's your 16" mainline minimum radius that would cause me the most doubt, but, you really won't know for sure unless you buy them and try them...and if you're looking for early Cab-Forwards, these are the only game in town.

Cheerio!
Bob Gilmore

[ATSF_Ron]

Thanks for the responses, guys.  I don't doubt Mark's expertise.  I also don't doubt the seller when he says it runs smoothly.  Maybe this one is a diamond in the rough.  Since it is returnable, I may bid for it and if I end up winning and the running quality isn't what I expect, then I'm only out the cost of return shipping.  I still have a few days to think on it.  Thanks again for all the feedback.

[spookshow]

The weird thing about the Sam Big Boys is that they run way better than the cab-forwards (or at least that's been my experience). Same basic mechanism, so who knows why the difference? Maybe the Big Boys were just put together better.

-Mark

[JMaurer1]

...or they weren't designed to run backwards.

[ATSF_Ron]

I decided to take a pass on the AC-6.  Reread Spookshow Mark's review and the comments from all of you and decided that even though it probably ran fine, I can't expand my minimum radius up from 16", realistically.  There just isn't space available. My Intermountain cab forwards are fine on 16", but I'm not willing to dump hundreds of dollars on a "maybe" brass loco at this point.  I'm an operator, not a collector.  I need locos that run reliably within the limits I have.

[ATSF_Ron]

Well, after talking myself out of this loco, I decided to bid and won!  It is truly a mint condition loco with little or no run time on a layout.  It's a bit noisier than I'd like, but that's typical for a lot pf brass.  I'm pleased with the general running quality, but it seemed stiff like it needed lube, so off came the gear covers.  Yep.  Bone dry.  I gave the gears some proper lube and am setting up a Unitrack test loop to help break 'er in for a bit.  At worst, I have 30 days to return it if issues crop up.  At best, I have an AC-6 that seems like it'll be a decent enough runner to join the fleet and can't be found anywhere else.  As far as the minimum radius issue, 19" looks to be the minimum, as Mark said in his review.  My layout is sectional, and I'm already irritated with the design of my 16" radius section anyway. So it'll most likely get tossed and redone with 19" or larger.  The bigger issue is the room size vs. layout configuration.  That's a topic for another day...

Anyhow, I'll post some pics of this beauty real soon!

[Chris333]

I had one for a few weeks. Never ran it on a layout, but did make sure it ran.

[ATSF_Ron]

A few "glamour shots," lol.

[ATSF_Ron]

You can really see the wide swing of this loco on a couple of these pics.  And this is on Kato Unitrack at 19" radius!  I'm thinking I'll go as wide as I can on my turnback curve of the new section I'm planning.  Maybe I can get away with 22".

[ATSF_Ron]

Lubing and running for just 15 minutes made a huge difference so far.  It's much quieter, though still noisy by Kato or BLI steam standards.  Definitely acceptable though.  One interesting thing is when it goes into a left turn there is a distinct clicking sound.  Not in a right, but only in a left.  As near as I can tell, it appears to be coming from the valve gear or possibly one of the drivers rubbing on something.  It doesn't affect the performance, but it's definitely something making contact.  When I put down some test rail I'll widen out the radius to test that and see if wider radius helps.  A nice surprise is whoever had this loco previously installed a headlight.  This is a "Classic" series loco, so no factory headlight.  So far I have no clue about pulling power as I don't have enough 19" curves to make a full loop.  Slow speed op is decent but not stellar.  Good enough to run a reefer block at about 25-35 scale mph.

Looks like it's a keeper at this point.  Hopefully things smooth out even more and quiet down some more.

[Chris333]

This was mine:
https://photos.app.goo.gl/4CdhhfJdA56icB1L7
Bought it at a show just to turn around and sell.