Paul D. North sent me an article about the BN branch in the Black Hills of S.D. To cope with the hills and curves, it said the CBQ used "heavy Consolidaions with blind second drivers". What does this mean, and why was it done?
Thanks to Chris / CopCarSS for my avatar.
A "blind driver" is simply a drive wheel without a flange. The second set (counting from the front) was the pair without the flange in this case, which was done to allow the rigid wheelbase of the locomotive to operate around sharper curves than a locomotive with flanges on all drivers.
By your title, I'm assuming you know what a "heavy consolidation" is.
In later years steam engines with long wheelbases were fitted with lateral motion devices to allow the drivers some sideways movement on tight curves. Some classes still required blind drivers to negotiate curves. The PRR 2-10-0 originally had the center pair flageless and later all three middle sets had no flanges. Don't know but I suspect the UP 4-12-0 also had blind drivers.
So, the blind driver doesn't have flanges, but it still provides power to the rails-right?
Murphy Siding So, the blind driver doesn't have flanges, but it still provides power to the rails-right?
Yes. In some applications the tread of the wheel on the blind drivers was turned flat instead of the traditional taper. Another variation would have the tread of the blind drivers wider than the tread of the flanged driver (counting the width of the flange).
ndbprrIn later years steam engines with long wheelbases were fitted with lateral motion devices to allow the drivers some sideways movement on tight curves. Some classes still required blind drivers to negotiate curves. The PRR 2-10-0 originally had the center pair flageless and later all three middle sets had no flanges. Don't know but I suspect the UP 4-12-0 also had blind drivers.
I think you mean the UP 4-12-2 and it did have a blind driver on the 4th when it was new. In later years, it had flanges on all six sets.
CZ
If anyone wants to see a lcomotive with blind drivers in action, Strasburg RR #90, a former Great Western (Colorado) 2-10-0 has a blind 3rd set (middle axle) of drvers. The tread of that driver is wider so that it is always touching the rail regardless of what type of curve it is on.
Going offshore, the very last new design steam locomotive built for the Japan National Railways (in 1948) was a 2-10-4T, designed for helper service on one particular grade (and taken out of service when that line was electrified.) The third and fourth driver sets were blind.
Chuck
If some of those rascals did not have blind drivers, they never would have gotten out of the yard (Plenty of broken stirrups, heel blocks and heel block bolts in the switch points plus shatterred frogs and guardrails/bolts.
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Possibly the most extreme example of blind driver use was on a class of 4-2-4T locomotives built in England in 1854. The Pearson Single class had only one driver per side, a flangeless monster just short of nine feet in diameter!
http://en.wikipedia.org/wiki/File:BER_2002_Exeter.jpg
Since they were broad gauge, there was plenty of room inside the frames for drivers, main rods, valve motion and the boiler. As for weather protection for the engine crew, in 1854 that wasn't a priority.
tomikawaTTPossibly the most extreme example of blind driver use was on a class of 4-2-4T locomotives built in England in 1854. The Pearson Single class had only one driver per side, a flangeless monster just short of nine feet in diameter! http://en.wikipedia.org/wiki/File:BER_2002_Exeter.jpg Since they were broad gauge, there was plenty of room inside the frames for drivers, main rods, valve motion and the boiler. As for weather protection for the engine crew, in 1854 that wasn't a priority. Chuck
I can't tell from the picture if that is flange less or not. What you are seeing is a shield in the picture, not the wheel. If you look closely, you can see two steps on that cover to allow someone to climb up.
One thing for sure, that early locomotive had almost no traffic effort, like one or two carriages??
CAZEPHYR tomikawaTT Possibly the most extreme example of blind driver use was on a class of 4-2-4T locomotives built in England in 1854. The Pearson Single class had only one driver per side, a flangeless monster just short of nine feet in diameter! http://en.wikipedia.org/wiki/File:BER_2002_Exeter.jpg Since they were broad gauge, there was plenty of room inside the frames for drivers, main rods, valve motion and the boiler. As for weather protection for the engine crew, in 1854 that wasn't a priority. Chuck Chuck I can't tell from the picture if that is flange less or not. What you are seeing is a shield in the picture, not the wheel. If you look closely, you can see two steps on that cover to allow someone to climb up. One thing for sure, that early locomotive had almost no traffic effort, like one or two carriages?? CZ
tomikawaTT Possibly the most extreme example of blind driver use was on a class of 4-2-4T locomotives built in England in 1854. The Pearson Single class had only one driver per side, a flangeless monster just short of nine feet in diameter! http://en.wikipedia.org/wiki/File:BER_2002_Exeter.jpg Since they were broad gauge, there was plenty of room inside the frames for drivers, main rods, valve motion and the boiler. As for weather protection for the engine crew, in 1854 that wasn't a priority. Chuck
The Wikipedia article http://en.wikipedia.org/wiki/Bristol_and_Exeter_Railway_4-2-4T_locomotives states that these were indeed flangeless. The Bristol and Exeter was an associate of the Great Western Railway and acted as a westward extension of the GWR's London to Bristol main line. I'm not sure what the gradients on the B&E are but the GWR main line was and is exceptionally well engineered, straight with very gentle grades, and designed from the outset for high speed running (which in those days meant huge driving wheels and very light trains). The original 7-foot gauge was chosen for stability (and thus speed/comfort).
The thing that catches my eye about the picture is the proper walkways with external handrails. Obviously in those early days crews were expected to go forward to oil the locomotive whilst running etc., but on British standard gauge locomotives the walkways were usually very narrow and the handrail ran along the side of the boiler, so going forward must have been very perilous. This locomotive had a much safer arrangement - provided you survived the climb over the driver, that is!
Until about eight or nine years ago, a light Mikado was used during excursions near Waas, BC, on Vancouver Island. I took a photo of the blind driver arrangement on this engine intended for tighter curves. Note that there are two sets, back-to-back, that are flangless.
-Crandell
Crandell
That little Mike probably would go around a very tight radius like an industrial area and still keep moving. You can spot the width of the two center drivers since the width runs right out to the place the flange would normally be.
Good picture and detail.
CZ\
kbathgateThe thing that catches my eye about the picture is the proper walkways with external handrails. Obviously in those early days crews were expected to go forward to oil the locomotive whilst running etc., but on British standard gauge locomotives the walkways were usually very narrow and the handrail ran along the side of the boiler, so going forward must have been very perilous. This locomotive had a much safer arrangement - provided you survived the climb over the driver, that is!
I believe they are flange less. The walkway over the top must have been exciting in rail and snow, if it ran during that time of year. I can't imagine climbing over that hump to walk along the boiler. In later years, many of the later steam engines used grate type material on the walkways so the ice and snow would melt and fall down instead of building up on the walkway.
selectorUntil about eight or nine years ago, a light Mikado was used during excursions near Waas, BC, on Vancouver Island. I took a photo of the blind driver arrangement on this engine intended for tighter curves. Note that there are two sets, back-to-back, that are flangless. -Crandell
James
The Butler...Lionel is vindicated?
Only by mutual consent if we can agree that Broadway Limited Imports did the right thing by making both their innner driver pairs on their HO Pennsy T1 Duplex blind. I'll make the first move and aver that they were.
CZ, thanks. Even I can take a decent image now and then.
The problems with mutiple drive axle rigid frame locomotives negotiating curves were known even from the early days of railroading. In 1842, Baldwin patented their flexible beam truck, where a pair of drive axles were set in a parallelagram frame so that the front two axles of an 0-6-0 could move side to side while being driven from side rods to help negotiate curves. This was before the advent of refined lead truck suspension. Later on, the flexible beam truck was applied to even heavier 0-8-0 types. Both types were intended to be road locomotives, not the switching locomotives that we normally associate with those wheel arrangements. With the advent of the four wheel spread truck with self-centering link suspension and the Bissell two wheel lead truck, the more common 4-4-0 and 2-6-0 wheel arrangements came into use. The 4-4-0 did not require blind drivers to negotiate sharp curves (in fact, with the self-centering four wheel lead truck, it had to have flanges on all four drivers), but the 2-6-0 occasionally did require blind drivers on the middle axle depending on the length of the rigid wheelbase and sharpness of curves. From that time on, it wasn't uncommon for locomotives with 6 or more drivers to have blind flanges on some of the wheels, and later locomotives with long wheelbases occasionally using lateral deflection devices on the front drive axle - shades of Baldwin's original solution! Even the some of the Mason Bogies had blind wheels or lateral deflection allowances on the center axle of the truck under the tender end of their larger locomotives.
'Tis a hard thing to make a rigid wheelbase go around a sharp curve!
- James
CAZEPHYR Crandell That little Mike probably would go around a very tight radius like an industrial area and still keep moving. You can spot the width of the two center drivers since the width runs right out to the place the flange would normally be. Good picture and detail. CZ\
Looking closely, the blind drivers are also wider in external dimension - overhanging the railhead by what appears to be about two centimeters more than the flanged drivers. I could see that being necessary to keep those drivers from dropping down inside the outer rail of a sharp curve.
Really nice, and informative, photo.
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