Will My Curves Support Engines With 8 Drivers?

[Brakeman Hal]

Hello,

I have a large 127.5-foot O-Scale 2-Rail folded dogbone layout with loops of 42" and 45" radius, and 90 degree turns of 45" and 50" radius. These are equivalent to 7' and 8' diameter circles.

My 4-6-2 Pacific and my GP-35 Diesels have no problem on these curves, and will take them at a brisk speed.

My question is, would an engine with 8 drivers be stable on these curves? I would like to get a 2-8-2 Mikado or a 2-8-0 Consolidation, to remember my Dad when he was a fireman on these PRR locos during the War years of the early 1940s.

Brakeman Hal, age 84

 

[Selector]

Gauge three rail yes, scale two-rail, probably not. Maybe a logging engine like a 2-8-2T with 53" scale drivers, but it depends on what the manufacturer intended the scale loco to be able to negotiate.*

*Just a SWAG; no experience whatsoever in anything O.

 

[Brakeman Hal]

Thanks, Selector...I guess that rules out locos with 8 drivers then?

Hal

 

[trailrider]

Thanks, Selector...I guess that rules out locos with 8 drivers then?

Hal

I am NOT familiar with O-scale, especially what the center 3rd rail would do to tracking, electrical contact. However, dividing your radii in half, in HO would equate to around 22-inch radius curves. With the caveat that my locomotives have blind (flangeless) center drivers, my 2-8-2's and even 2-10-4'a will handle those curves. on the ten-coupled locomotives, I shim the blind drivers about .010" above the level of the rails, so they don't catch on the rail heads coming out of the curves. Don't know if this will be of some help or not.
Stay well and safe!
Merry Christmas!

 

[Selector]

Thanks, Selector...I guess that rules out locos with 8 drivers then?

Hal

Hal, if you have a specific hankering, and you have identified the supplier/importer, would their website have that information? Maybe the loco CAN negotiate the curve radius you have in place. In HO, BLI and Bachmann, as examples, are careful to spell it out so that they don't have disappointed and vocal forum-dwelling former clients.

 

[Brakeman Hal]

I would speak to the supplier on the telephone, to be assured or disappointed.

Hal

 

[Brakeman Hal]

OK, then what is it with O-Gauge Lionel layouts, no bigger than mine, which will allow operations with 4-8-8-4 Big Boys and 4-6-6-4 Challengers? Is it something in the spacing of the trucks from the drivers, or having blind drivers except for the leading and trailing drivers or what?

I like the O-Scale equipment better than the O-Gauge stuff because it's more prototypical, yet the vast majority of O operators will cling to the Lionel O-Gauge, and ignore that un-natural center rail, which I couldn't, having a railroad heritage.

If I can't duplicate my Dad's experience on 2-8-2 Mikados and 2-8-0 Consolidations, I would have to go with a 2-6-0 Mogul or a 2-6-2 Prairie for my short-line light freight train. The 4-6-2-Pacific I have just doesn't seem to "fit in" with a freight train.

Brakeman Hal, swinging my lantern for "all clear" and getting a toot from the Hogger.....
View attachment 122151

 

[Selector]

The O Gauge stuff used to be called 'high rail', 'tin plate', and has always been more toy-like, and built to appeal to a person who had 'Christmas' train sets, stuff easily assembled and run, very forgiving...robust, that takes some rough handling and tumbling off of the sharp curves. Some of it is finer than others, but it's still gotta go around those three-rail tracks. So, more sideplay in the rods with longer pins that permit the various rods to slide and the wheels to move sideways relative to the frame. It's called 'lateral motion device' in the real world of steam. Very sophisticated, just not in the toys.

O Scale is the larger equivalent of HO, which has a long history of being more prototypical in the non-train set market. O scale offers the finer details, more scale fidelity, and of course only the two rails instead of the toy-like third rail and very tight curves.

So, the drivers are more accurately made and placed on a frame that is true to the prototype, and so does everything else come very close. It's what makes those scale representations cost three-six times as much. Yes, they're all still toys, but...they're finer, more realistic, and so they have to BE RUN more realistically, meaning on the wider curves. There would normally only be blind drivers if the prototype had them, but not necessarily. The BLI HO T1 Duplex 4-4-4-4 has its two middle axles blind so that it can get its true-to-prototype non-articulated chassis through our tight HO curves. It really is a take-it-or-leave-it proposition.