Sunset Models 2-10-2 Radius Question

[boatwrench]

By any chance does anyone know the minimum radius this locomotive will run on? Last time I ran the locomotive was on a club layout pre DCC in the late 1980s pre-DCC era. It is one of Sunsets budget line of brass locos that were selling for $100-$150 purchased 1987-88 time frame. It does have a blind middle driver. I am debating should I convert to DCC or just leave it on the shelf. The photo is a stock photo, the locomotive I own is a custom painted for the Southern Railway by the late Mel Horne. My current shelf layout has one curve which is 22" radius but I have acquired more real estate to expand the layout.


thank you

 

[kjd]

I have a PFM Prairie that shorts out on 24" curves so would imagine that would take Extra Large.

 

[D&J RailRoad]

No sense in just having it sit on a shelf. Ya might as well send it here to get some good running.

 

[Sirfoldalot]

I cannot attest to it, but I would think that 22 inch would be sufficient?

I have a PFM 2-10-0 that operates nicely with 18 inch and #4 turnouts.
Hope this helps.

 

[trailrider]

It just depends on how much sideplay there is on the other drivers. There is a trick I use with my kitbashed 2-10-2's and 2-10-4's made from Mantua 2-8-2's. I blind flange all but the end drivers, and then shim the blind drivers up .010", and the flanged end drivers down .010", leaving the center drivers off the top of the rails. That way the blind drivers don't catch on the tops of the rails coming out of a curve. Making sue the lead and trailing trucks have enough play to swing with the curve, I can run them on 18 - 20 inch curves. But I have no idea what your locomotive can handle, especially if the driving axles are sprung.

 

[Selector]

My 2012 Sunset CPR 2-10-4 says 30" , and they mean it. Count on at least 24" if it's a Decapod chassis, but if it's fairly true to prototype, you'll need close to 26-28". and that's being optimistic.

 

[Espeefan]

My 2012 Sunset CPR 2-10-4 says 30" , and they mean it. Count on at least 24" if it's a Decapod chassis, but if it's fairly true to prototype, you'll need close to 26-28". and that's being optimistic.

I would guess 30" but there's only one way to find out. Try it. I believe 22" is too small for most anything brass larger than a small 2-8-2. it will depend on the lateral play in the driver set. In general, brass doesn't do well on snap track radii.

 

[boatwrench]

Thanks for all the replies and suggestions. I dug out some old flex track and laid out 22r, 24r and 30r for a test. On the left is some sectional 18R I knew would workout but placed for the photo. The 22r & 24r are code 100. The locomotive from a slow start runs without derailing on the 22r but the middle driver is not on the rail and looks awful. The pilot truck derails while reversing. On the 24r runs better and looks better forward and reverse with all wheels remaining on the rail. The 30r, if only I had the room, no question or worries about performance.

Again thanks for everyone's suggestions and replies. Will need to really figure out what to eliminate in order to press this locomotive into pusher service.

 

[Selector]

... The locomotive from a slow start runs without derailing on the 22r but the middle driver is not on the rail and looks awful. The pilot truck derails while reversing. On the 24r runs better and looks better forward and reverse with all wheels remaining on the rail. The 30r, if only I had the room, no question or worries about performance...

This tells me more, and I believe your engine has a 'blind' center driver axle. No flanges. This was fairly common on industrial steamers with six or eight drivers working on tight curves. My Paragon Broadway Limited Duplex T1 4-4-4-4 has both inner sets of drivers blind. It will handle 22" radii, but it looks goofy. The center axle on my Paragon J1 2-10-4 is also blind.

 

[bnsf971]

Just a suggestion, but if you don't have any sentimental interest in it, and you're not a Brass Snob, why not sell it, and use the proceeds to get a new model 2-10-2 that will operate on your layout, already be painted and lettered, and will most likely look and run better than what you have now?

 

[trailrider]

This tells me more, and I believe your engine has a 'blind' center driver axle. No flanges. This was fairly common on industrial steamers with six or eight drivers working on tight curves. My Paragon Broadway Limited Duplex T1 4-4-4-4 has both inner sets of drivers blind. It will handle 22" radii, but it looks goofy. The center axle on my Paragon J1 2-10-4 is also blind.

The center drivers on my kitbashed 2-10-2's and 2-10-4's (from Mantua Mikados) are all blind. Just the end ones have flanges. I think the wheel base is probably shorter than your engines, but they don't look bad on 20-inch radius curves. If you don't mind, it don't matter! BTW, the prototype T-1's were restricted as to where they could run because of their long wheelbase. Restricted to running between NY and Chicago.

 

[boatwrench]

Just a suggestion, but if you don't have any sentimental interest in it, and you're not a Brass Snob, why not sell it,

There is sentimental value as I admire the work of the painter. He was an avid SP steam modeler and one of the best painters I ever knew. He passed away over a dozen years ago and I had contacted his estate about acquiring some locomotives from his collection. Now I just watch eBay for SP steam being auctioned off in the Seattle area and inquire if the seller knows who painted the locomotive. Yeah, it's all about sentiment.

 

[bnsf971]

There is sentimental value as I admire the work of the painter. He was an avid SP steam modeler and one of the best painters I ever knew. He passed away over a dozen years ago and I had contacted his estate about acquiring some locomotives from his collection. Now I just watch eBay for SP steam being auctioned off in the Seattle area and inquire if the seller knows who painted the locomotive. Yeah, it's all about sentiment.

Okay, since you have a good reason to keep it, you may be able to find two more pairs of blind drivers for it, which will help it go around tighter radius curves. If you can, the second driver and the last driver would be good candidates, as well as a longer drawbar since the rear will pivot outward more. My suggestion of the last driver being blind, rather than the center three, is so there will be less of the drivers coming completely off the rails on the curves.

 

[trailrider]

Okay, since you have a good reason to keep it, you may be able to find two more pairs of blind drivers for it, which will help it go around tighter radius curves. If you can, the second driver and the last driver would be good candidates, as well as a longer drawbar since the rear will pivot outward more. My suggestion of the last driver being blind, rather than the center three, is so there will be less of the drivers coming completely off the rails on the curves.

Unless the drivers are sprung, i.e. have spring suspensions pushing the drivers down on the rails, you might shim the blind drivers with .010-.015" shims under the axles, and the same amount of shim above the flanged drivers. This will keep the blind drivers off the tops of the rails, insuring that they don't catch on the top of the rails when the engine leaves the curves. Unless you get right down at the top of the track, with a light behind the drivers, you really can't tell they don't touch the rails. The only disadvantage to making the rear driver blind is that you may not have enough clearance to swing the trailing truck, and you no doubt will need to lengthen the drawbar.

One other thing, if you do find some additional blind drivers is that you may have to requarter all five sets. I usually disconnect the drive mechanism and push the chassis to be sure there is no binding in the set with any new drivers. Usually I can get away without requartering, but every once in a while it becomes necessary.

If all this sounds like a lot of work and you don't want to bother with it, you can just send me the locomotive. I won't charge you to take it off your hands. <rolleyes, grin>

 

[Slobbering Pennsy Freak]

I had a problem with a PFM PRR 2-10-0 with blind drivers. It took a very close look at the drivers to find the problem. It went around a 24" radius curve and derailed. The cause was a road crossing the track at grade. The tiny wood strips next to the rail were a tiny fraction higher than the rail. When the blind driver hit the wooden strip it lifted the drivers off the rail and onto the road.

 

[Iron Horseman]

The 30r, if only I had the room, no question or worries about performance.

Interesting, that was my first thought when I read the leading post. 30" minimum radius. When I was originally planning my first HO layout after switching back from N in the 1970s, I decided 30" minimum because every brass loco I wanted had that requirement, save one of the Hudson's which was 28".

I would not make more blind drivers, without increasing the flange depth on the remaining ones. This is a brass model with RP25 or finer flanges. The more blind the greater stress on those remaining.

I would just run it gingerly around the tighter curve, and not back it up.

 

[Slobbering Pennsy Freak]

I agree. The PRR had restrictions on its tight curves in the Middle Division near Iron Furnace and Spruce Creek. So make up a rule for your operating sesion.