Hi folks, I own the IHC Sante Fe 2-10-2 and always wondered why the center drivers are flangeless. I just looked at my Bachmann Spectrum Decapod 2-10-0 and its center drivers are also flangeless. Now it gets interesting. I read the history of the Sante Fe in the IHC box and it says the Sante Fe was a descendant of the Decapod, on which the rear truck was added for guiding because Decapods would back down the Raton or Cajon passes and pick up the next upgrade train. Thus the new name Sante Fe after the railroad that put the trailing truck on.
Anyway, did the protoype Decapod lack the center driver flange, and then likewise the prototype Sante Fe? Why would both scale model lack the center driver flange unless they were both copying the prototype? I can’t tell from prototype photos.
Photos and drawings in Kalmbach’s Steam Locomotive Cyclopedia of the prototype (Russian) Decapod and Santa Fe’s 3800 class 2-10-2’s show flanges on all drivers. Generally, steam locomotives had all drivers flanged. There were exceptions, though. The Pennsylvania Railroad was notorious for forgetting to flange all the drivers–their 2-8-0’s and 2-10-0’s come to mind. Also, as I recall, the UP 4-12-2 had one or more driver pairs unflanged.
While the drawing of the Russian Decapod shows drivers on all flanges, the ‘as built’ photo and at least two others show blind main drivers. However, the other photos are of locos that obviously have flanges on the main drivers. I guess the individual railroads, “Paid their money, and took their choice.”
As far as I can determine, the AT&SF 2-10-2s had flanges on all of their drivers.
Some time back, Crandell (Selector) posted running gear photos of a 2-8-2 with blind second and third drivers. The blind drivers had wider, un-tapered tires.
The earliest UP 4-12-2s had blind drivers. Experience proved that the other arrangements which made them flexible enough to round curves also made it possible to run them with all drivers flanged.
Blind drivers were very common in the 19th century. Probably the most extreme example was the class that also had the tallest drivers ever run. It was a 4-2-4T, and depended on the swiveling trucks to keep the wide-tired ‘single’ drivers on the 7’ 1/2" gauge rails! However, they weren’t solely a 19th century phenomenon. JNR’s E10 class 2-10-4T, the last-designed class of Japanese steam for domestic service, was built in 1948 with blind main and #4 drivers.
As noted above, some manufacturers have put blind drivers on models of prototypes that had all wheels flanged - part of the compromise engineering required to make
As far as I know, the Southern Pacific, which operated a very large number of “Dec’s”, which they called their “F” series 2-10-2 steamers (so they didn’t have to call them “Santa Fe’s”, LOL) had lateral motion devices installed in the wheelbase on the first and third drivers to allow them to take the tight mountain curves prevalent in the SP territory of California and Oregon. I don’t know of any SP “Dec’s” that had blind center drivers.
On the Rio Grande, their very large 1916-ALCO built 2-10-2’s (designated “F’s” for “Freight”, like SP) tended to try to ‘straighten’ out curves on both the Moffatt and Tennessee Pass mainlines, so they were eventually relagated to the easier curves over Soldier Summit, Utah, where they spent most of their lives either hauling or helping coal trains. I don’t believe that ALCO designed these large locomotives with lateral motion devices on the drivers. I do know that at the time of their building, they had the longest non-articulated wheelbase and the heaviest tractive effort (81,000 pounds) of any 2-10-2 yet built. But again, no blind center drivers.
Most brass models of 10-drivered locomotives are designed for larger radii, and have closer to scale tolerances (though less than actual prototype), while many manufacturers of plastic RTR steam are wanting to reach a larger segment of steam modelers (good for them!), and usually end up blanking the center driver in order to accomodate smaller radii.
So if your IHC 2-10-2 has a blank center driver, it’s designed to get it around a smaller radius curve, and not probably prototype practice.
However, from what I’ve read of other model railroaders that have purchased the IHC2-10-2, you have yourself a VERY good basic steam locomotive.
When first built the PRR used flange less drivers on their decapod on the center three axles but after a few had dropped off a rail and caused some costly damage and delays they flanged the front two and rear two and left the center un- flanged. But, some went to the scrapers with three flange less axles. Lateral motion devices were very costly to maintain and created wear in parts that needed frequent replacement. Ride quality also suffered with lateral motion. Crews would get tossed around inside the cabs violently. Although they could run at better than fifty MPH they were better suited and safer for slower drag freight at speeds under 30.
Simply put, yes. the center driver lacked flanges. I got to see the ATSF 940 (a 2-10-2 built by Baldwin) be moved via truck to a new location in Bartlesville, OK. IIRC, the second and fourth axle of the driving wheels had smaller flanges. I could be wrong there, but it has been a while since I got look at it that close.