Steam & Excursion > blind drivers

What was the purpose of,on some steamers,having some of the middle drivers flangeless or "blind" as I heard an old head call it? Was it so that the bigger engines could negotiate turns better? He was off the Pennsy,was this practice indigenous to the PRR?
PC

Blind drivers (flangeless drivers) help a locomotive negotiate sharper curvature without "binding up." They were commonly found on locomotives used on mountain railroads. Most narrow gauge locomotives had one or more pairs of blind drivers. Obviously, they were usually the middle sets of drivers. For example, on a 2-8-0, the second and third pair of drivers would generally be the blind ones, with the first and fourth pair flanged.

WW Wrote:
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> Blind drivers (flangeless drivers) help a
> locomotive negotiate sharper curvature without
> "binding up." They were commonly found on
> locomotives used on mountain railroads. Most
> narrow gauge locomotives had one or more pairs of
> blind drivers. Obviously, they were usually the
> middle sets of drivers. For example, on a 2-8-0,
> the second and third pair of drivers would
> generally be the blind ones, with the first and
> fourth pair flanged.

Correct, WW.

These were not unique to the PRR, either, as PennCentral00 suggested, but they sure did use it. PRR's big I-1 2-10-0's only had flanges on the first and fifth driving axles. Their huge fleet of fantailed H-1 2-8-0's also had blind middle pairs of drive wheels.

They were used on mountain railroads, but were not uncommon on flatland engines, as well. And though one would think they could only be used on middle sets of drivers, a lot of 2-8-0, 2-10-0, 4-6-0, and 4-8-0 engines had blind leading drivers. IIRC SP's "El Gubanator" (the lone member of the 4-10-0 design) also had a blind lead driving axle.

It was also common on blind tires to make the tread a tad wider than a standard flanged tire, in order to help keep it from dropping between the rails on a tight curve.

Sierra Ry. 2-8-2 #34 has at least one set of blind drivers.
One locomotive that maybe should have been built with a set is former Hammond Lbr. 2-8-2T #17...hers are all flanged. Alco equiped her with a lateral motion device to compensate for this. She is right at her curvature limits on Mount Rainier Scenic's loop @ Mineral Lake, WA.

Tom

UP 4-12-2's had one or two blind drivers when built (maybe just the first orders?), but all flanged was the standard later. I have seen a photo of one taken ca. 1947 that sure looks like one driver is blind. Perhaps a flange was worn to the limit & rather than re-tire the wheel, the shop just turned it blind? Maybe a UP steam-era expert could clarify if this was an acceptable practice for the 3rd or 4th drivers in 9000's later on.

UP's first 4-12-2 was constructed and delivered with the 2nd and 3rd driving axles blind. However, before the engine entered service UP fitted the 2nd axle with flanged tires. Not long after, the 3rd axle also received flanged tires. The 4-12-2's had lateral motion devices on the 1st and 6th driving axle which greatly eased curving.

To my knowledge no other 4-12-2 was ever operated with blind tires, and such was definitely not standard practice in later years.

John

4-12-2 Wrote:
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> UP's first 4-12-2 was constructed and delivered
> with the 2nd and 3rd driving axles blind.
> However, before the engine entered service UP
> fitted the 2nd axle with flanged tires. Not long
> after, the 3rd axle also received flanged tires.
> The 4-12-2's had lateral motion devices on the 1st
> and 6th driving axle which greatly eased curving.
>
> To my knowledge no other 4-12-2 was ever operated
> with blind tires, and such was definitely not
> standard practice in later years.
>
> John

John, thanks for answering that. Somewhere in my collection, I have a series of slides by the late John Hungerford of the
UP 9000 being "walked" very carefully throught the curves at Summit, CA while on her way West for eventual display. She
was under steam on a cab hop.

Tom

Thanks to all that replied and to the ones that haven't as of yet.The information was very interesting.
PC

And then there are all those Lionel #736's..........., aka the "Blind Berks."

Alco's drawings of these engines, published in the Railway Mechanical Engineer and in Railway Age in 1926, showed a blind 4th driver. Linn Westcott's Steam Locomotive Cyclopedia, Vol. reports that "Origianlly the fourth drivers had no flanges, but this was found unnecessary."

Photos of these engines that I can find seem to show flanges on all drivers.

Thanks for your further information.

MTMEngineer, actually, those weren't Alco's drawings in the RME, Railway Age or Locomotive Cyclopedia, they were in fact Simmons-Boardman's drawings. Still, they were made from drawings provided by the builders, suppliers and others.

I sure won't try and go into it all here as it's much too long a story, but the reason all the "public" images (both drawings and photos) of 9000 display only 4th driver blind drivers is because they were either made during or from the engine's configuration as it began road trials.

UP Mechanical Dept. draftsman/engineer John Mohun's patent drawing, and Joe Davenport's official "sketch" (drawn for UP officers and Board in NY) show blind 3rd and 4th. More, a very keen eye on Alco builder's photos of the 9000 will make clear both the lack of flange as well as the 1/2" wider tires on those two driving axles.

Union Pacific didn't believe the blind drivers were necessary, but Alco was very interested that their engine show well and not suffer tracking problems which would invariably lead to bad press (this was much a joint venture in certain ways....remember, it's 1925 and what's just happened to the steam locomotive market over in Ohio at that little Lima company?....both Alco and Baldwin were keen to combat the burgeoning super power movement).

As I mentioned earlier, UP replaced the blind tires on the 3rd axle during initial setup in Omaha Shop. The 4th was replaced in a very short time, I can't remember with certainty right now, but within the month sticks in my mind.

Anyway, it's something I found very interesting when I discovered it.

John

In later years as self-guarding frogs became common, the blind drivers that had extra width tires became a real issue and some routes were off limits to such locomotives.

Jim700 Wrote:
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> In later years as self-guarding frogs became
> common, the blind drivers that had extra width
> tires became a real issue and some routes were off
> limits to such locomotives.

Good point Jim...the same could be said for the wider tires found on many geared locomotives.

Tom

Hmmmm...this is interesting! So, a self-guiding frog was a device with limited dimensions ("width?") and the wider tires would foul them, eh?

Obviously, I don't know much about trackage, but does this mean roads like Pennsy, who had quite a number of such engines in all types of service, didn't have many of these switches? Perhaps these engines weren't involved in interchange to any extent.

By the same token, I'd assume the "transfer roads" like EJ&E, which would by necessity interchange with a great many adjoining lines, had very few engines with blind tires at least in the later years.

Yes, that's also true of the Russian 2-10-0's that found their way to a lot of US roads in 1918, and to most of the Milwaukee's Little Joe electrics, which were regauged from 5' gauge by applying wide tires.

OK...question about Russian Decapods, such as the Frisco 1630 IRM has (waiting for running gear work but other wise a runnable engine). They fitted these things with wide tires that extend farther inboard to achieve standard gauge while wide enough outboard to continue to grip the driving wheel centers that were designed for 5' gauge. (One presumes they simply replaced the pony axle.) My question is this: If there's that much room inboard that this is possible without the wide tire striking the frame* why didnt they, over all those decades of service, press the wheels onto shorter axles (with longer crankpins)? Seems like it would have been worth it to enable the use of conventional tires and remove any restrictions about the engines and frogs etc.

* Actually this is pretty much what has sidelined the 1630 as the tires were rubbing on the firebox but that's because of too much play in the driving boxes

That's a really interesting one!

It would surely seem normal to have taken the tack you mention, but perhaps the engineers decided the pins would be too long (which I doubt). My guess is they simply didn't want to spend the money on them, that it was cheaper to mess with the non-standard tires.

FACT:

Not all blind drivers are restricted from traveling through self-guarded frogs. I have personaly seen a B&LE 2-10-4 travel through self guarded frogs. The B&LE 2-10-4's are equipped with the #3 blind.

ALCO shipped the 4-12-2 with blind driver in order to allow the long rigid wheel base locomotives travel the shipped route. Curvature in the east is not near as broad as what is found in the west and the plains.

RealSteam, you're correct about the shipping of 9000, however Alco wanted those axles blind and UP didn't. There was correspondence back and forth on the matter.

John