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question for brass owners ho 4-8-4 minimum radius

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  • Member since
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question for brass owners ho 4-8-4 minimum radius
Posted by bobbygreg on Friday, November 9, 2018 12:06 PM

There is a Rock Island R-67  hallmark brass 4-8-4 that i am really interested in, I have 28 in radius curves and #6 turnouts on the main, #4 in the yard. My question is will it operate satisfactorly with those curves and turnouts.  Seems I heard or read somewhere that brass engines are not as flexible when it comes to radius and turnouts, as for example a bachmann spectrum 4-8-2 which I have. It would probably be a display  item most of the time but you know I would just need to run it on occasion. Anyway I appreciate any thoughts.  

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Posted by tstage on Friday, November 9, 2018 12:18 PM

bobbygreg,

There's no denying that a 4-8-4 is a beast.  It could operate well on your layout with that configuration...or, it might not.  Every brass locomotive is different - even from the same manufacturer.  Do you know when Hallmark released that 4-8-4?

Newer brass (1980 or >) will probably have a better chance of tracking than older brass.  I recently tested an ['88] OMI 2-8-2 Mikado and a ['78] NJ Custom Brass 0-10-0 switcher on an extened loop of track with R22" curves.  Both operated just fine without derailing but I didn't have any turnouts to navigate through.

I did find a couple of shorts with the 2-8-2.  However, a few aptly placed pieces of thin Kapton tape on the underside of the frame above the front & rear trucks resolved that issue quite nicely.

Bottom line: The only way to know for sure is to purchase it and see what happens.  Worst case scenario: It become as shelf queen.

Tom

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by gmpullman on Friday, November 9, 2018 12:36 PM

Hi, BG

Tom is spot-on with his reply that the operating characteristics of brass is definitely a case-by-case situation.

I have an old PRR 2-10-2 that negotiated 26 inch radius curves just fine yet some of my smaller-wheelbase engines stumble on the slightesd irregularity in the track.

Sometimes the tolerances of the brass details is so close that any slight curve or misalignment will cause a short.

In the case of your Rock Island 4-8-4 I took a look at the underside:

 CRIP_4-8-4 by Edmund, on Flickr

I was curious to see if there were any "blind" drivers — there are not. Another thing I would be concerned with are the soldered brass wire brake beams. Even if there was plenty of lateral slop, which it looks there might be, it is possible that a driver tire may touch one of the brake shoes on a curve. Some builders use plastic brake hangars and shoes for this reason. Sometimes you can get away with a little careful filing or possibly the clear nail-polish trick.

Looking again at the photo, I suspect that pilot truck would certainly give you trouble. Very little clearance to the cylinder wrapper. 

I recently installed a decoder and painted a Westside B&O Q-4b Mikado. One of the members here wondered if I had any tracking troubles with it as he understood that these engines didn't tolerate "sharp" curves very well. In this respect I had no problems but I did have to make several adjustments to the pilot wheels to get clearance under the cylinder saddle. Kapton tape helped a bit here.

Will you be running this loco using DCC? That makes a big difference in the tolerance for a brief short to give you headaches. Before I installed DCC on my layout, brass engines would run and if there was a quick short, as often happens, the inertia of the engine/train would be enough to keep things rolling.

A friend brought a dozen of his brass engines to run on my layout one day. Some of them had not run in years but we tried them out anyway. Some of those engines were sparking like old Dogem cars but, with a big DC power supply they kept plugging away.

So, bottom line is, that 4-8-4 might just do fine on your layout. Or you may have to track down a couple of trouble spots and try to eliminate a short or two. 

Knowing this going into the deal may sway your decision. Still, a nice brass model makes a nice museum piece and, who knows, someday you may have a layout with nice broad-radius curves.

 Hope that helps, Ed

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Posted by SeeYou190 on Friday, November 9, 2018 12:39 PM

tstage
Every brass locomotive is different - even from the same manufacturer.

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100% completely true.

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There is probably no way to know unless you try it.

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All my USRA 4-8-2s and 2-8-2s from Sunset and Key will negotiate 22" radius curves.

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My USRA 4-8-2 from Akane will not. It requires 28" curves, so it is a prop.

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-Kevin

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Living the dream.

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Posted by Howard Zane on Friday, November 9, 2018 12:41 PM

The R67 will not like your 28" curve, but worse than that.....not look to great. One should pick motive power to go with track limitations, or pick track work to go with your motive power. Some 4-8-2's or 2-8-4's possibly could make the curve or smaller articualteds such as 2-6-6-2's would work well as they are not rigid frame.

I feel that a 2-8-2 would or should be the maximum rigid frame loco for a 28" radius. Of course this is not in concrete....just my opinion.

HZ

Howard Zane
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Posted by 7j43k on Friday, November 9, 2018 12:49 PM

Big steam deserves big curves.

But.

PFM advertised that my GN 4-8-4 would take 22" curves.  It did.  It does still.  But it looks SO embarrassed.

Your 4-8-4 may vary.

 

Ed

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Posted by Howard Zane on Friday, November 9, 2018 3:17 PM
During the early days of brass....50's and 60's, PFM models, mainly Atlas (United) and Tenshodo were designed to operate an 22" curves. Just the rignt amount of driver side play was built in. Pony truck wheels were small so as not to hit lower steam chest. Check out a PFM PRR K4 vs a Red Ball, or some of the later versions of this 4-6-2. You'll notice how small the pony truck wheels are...I think 33" or about vs. the prototype 40" which are on other imports. Actually and sort of unfortunately, United 4-6-2's including the magnificent C&O F17 and F19 kept the smaller pony truck wheels, though as we got closer to the 80's and beyond the 22" common use radius fell out of favor. Both PFM ATSF and GN 4-8-4s could transverse 22" radii, but they'd look ridiculous...sort of like a large Lionel 2-8-4 726 on an O guage curve which was a 31" circle...and not a radius.

HZ

Howard Zane
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Posted by oldline1 on Friday, November 9, 2018 3:45 PM

I have operated several of my 4-8-4's on my old layout. I used code 83 24"r (flextrack) and #4 & #5 Walthers track and turnouts.

I used my Pro Custom Hobbies and NKP Western Maryland J-1 4-8-4's and my Sunset 1st and 2nd run N&W J and J-1 4-8-4's. They ran without any issues other than really looking awful with all that overhang!

oldline1

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Posted by 7j43k on Friday, November 9, 2018 3:52 PM

Howard,

It gets better:

D&RGW 2-8-8-2    20" minimum radius

ATSF 4-8-4           20"

GN O-8 2-8-2        20"

ATSF 4-6-4           18"

 

I added a 22" outside loop on my sad little layout just so I could run my GN 4-8-4. Sure, it looked funny.  But.  It also looked magnificent!

 

Ed

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Posted by PRR8259 on Friday, November 9, 2018 10:48 PM

For those folks wanting the look of brass on a budget, the BLI and other brass "hybrid" steam offerings are deliberately designed with more than average lateral motion in their drive axles and "looser" valve gear to allow operation on 22" radius curves.

Though I myself do not have curves that tight, I can attest that the BLI GN S-2 4-8-4 will very easily negotiate 26" minimum radius curves.  Heck, even the BLI UP 4-12-2 will do 26" minimum radius curves...but as Howard said, it may not look so great doing so.

John

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Posted by bobbygreg on Saturday, November 10, 2018 7:59 AM

Thanks for the replies, you confirmed what I had suspected.  I don't know when hallmark released it and the layout is dc. Anyway, not at all  sure  about spending $$ on something that I might not be able to run, although it would make a nice display. Again thanks for the replies.

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Posted by SeeYou190 on Saturday, November 10, 2018 8:30 AM

Yes, big steam deserves big curves.

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However, I need to be able to turn the train around at the end of the room, so all my end curves are 22 inch radius. These will all be hidden to prevent as much embarrasment as possible for the poor model.

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Visible mainline curves will all be 30 inches or greater, but I still need locomotives that will negotiate a 22 inch curve so they can make the turn at the end.

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Anything that will not do this becomes part of the "prop fleet" for photos only.

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-Kevin

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Living the dream.

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