How many driving wheels on an engine…Example: A
2 10 4 [o00000oo], did not have flanges…? I seem to remember some of the wheels in the center of the configuration were without flanges in order to make the sharper radius curves. Comments please.
QM
I read some PRR steam had flangeless drivers.Not sure how many railroads used this idea.Might post more later.
…Thanks for the comment. I’m rather sure I actually saw such configurations many years ago…either on the Pennsy or B&O…The RR’s I was around.
QM
I believe PRR had some 10 wheelers (ooOOO) sp built. These in turn migrated to the Ong Island and the PRSL.
Sorry…that’s Long Island. Fat fingers is my excuse.
It’s difficult for me to understand how a ridged framed locomotive with say…5 driving wheels in line and all with flanges could have nogotiated sharp radius curves without damaging the track gauge. Articulated engines of course would have the advantge of less driving wheels on a frame in a row. And yes I realize there where some articulated with at least 5 wheels in a row but probably not many.
QM
You mentioned the reason for blind drivers before…to negotiate tight curves. You do realize, I suppose, that with blind drivers, some stability is sacraficed. As far as larger locomotives skewing track guage, don’t underestimate the quality of track construction and the stabalizing effect of rail anchors, spikes, ballast and curve elevations. gdc
I really don’t know what effect the flangeless drivers would have had on stability…but I suppose it would have been an issue…And thinking about this situation with the larger engines with many drivers in line, they probably were limited to where they could take them as in yards with the sharp curves…etc.
QM
I am fairly sure the PRR 2-10-0 and UP 4-12-2 had at least one pair of blind drivers. I typed blind drivers locomotive into the Yahoo search engine and got over 1000 results.Most of them are about blind drivers running into locomotives though.
…For sure, watch out for blind drivers. And an engine having 10 or 12 driving wheels [5 or 6 in a line], surely would have to have some relief to make any kind of severe curve out of switches, etc. or tear up the rail structure…
QM
I can now answer my own question I posed at the beginning of this post…So we’ll pass it along. I went into Google and queried on the subject and found under 3-cylinder engines…Example: Union Pacific 4-12-2 number 9000 had “blind drivers” installed on the 3rd and 4th driving axles.
QM
I was digging around in the back pages of this forum and found this topic.
I just want to add that I remember seeing an old steam locomotive in the Kansas Museum of History in Topeka and noticed the absence of flages on some of the driving wheels. It was an old 2-8-0 consolidation. I remember that every other one had a flange. I can’t remember if it was the 1st and 3rd driving wheels or the 2nd and 4th. I also remember two of the driving wheels had smooth edges and two had rough or corrugated edges. I don’t know if this was for traction or is just the way it turned out in the restoration.
I did some seaching on the internet and found the website to the museum and it has all the technical specs. of the locomotive. http://www.kshs.org/cool2/train.htm
The thing you have to remember on all these longer wheelbase locomotives is that drivers aren’t as horizontally rigid as most of us think they are. First of all, many locomotives all the way down to 0-6-0 switchers had blind drivers. It just varied from railroad to railroad in how tight the curves in their yards were (where blind drivers were primarily needed). On the main line the lateral force the drivers would exert because of the wheelbase is lessened by the common practice of simply widening out the gauge a little, even a small change in that makes a big difference in the equipment, even for today’s trains. Besides that on a lot of older locomotives they were simply designed with a certain amount of slack in the rods and running gear to accomodate curves. Later in locomotive design on the Pennsy especially the running gear was specifically designed to move to follow the curves. In some case locomotives designed like this even up to 2-10-0’s didn’t even need blind drivers! Hope I’m not rambling too much for this to help you out!
Tim Sheffield
Locomotives had some lateral motion in the drivers to negoiate curves. Blind drivers added to that.
An example of an engine with blind center drivers is an ex-LNE 0-6-0 in the Ill Railway Museum at Union. It was used at Catasaugua to handle interchange cuts around a tremendously sharp curve between the LNE and the RDG.
Dave H.
In addition to blind drivers, some locomotives were also equipped with lateral motion devices to help negotiate curves. These would allow a few inches of lateral play on the axle equipped with the devices. Such devices would also prove useful on switchers with no pony trucks to allow higher speeds in occasional road service.
…In seeing activity on this post I didn’t realize it’s been so long since I originally asked the question…And just in the last few days I was looking at a website of model trains and noted “blind” drivers even on some of them.
In the lateral motion devices…I wonder how the designers kept that feature from inducing “hunt” as it went down the tracks…?
Almost all long wheelbase steam engines had one or more drive axles with blind drivers (no flanges). The definition of ‘long’ varied somewhat, but they were moderately common on engines with four driving axles (e.g. 2-8-2, 4-8-2, 2-8-4, 4-8-4) and… well, sweeping generalizations are dangerous, but I think it would be correct to say universal on engines with five and six friving axles. This prevented long wheelbase engines from behaving as rail straighteners (they did anyway, but that was the idea). Lateral motion devices helped, also.
Guidance for steam engines was generally assumed to come from the engine (lead) truck, the first and last driving axles, and the trailing truck – if any. In the lateral motion devices on all these trucks there was a lot of friction (in spite of copious lubrication) which helped control hunting. Even so, as I’m sure some of the old heads on this forum could tell you, at certain speeds even the best engines would hunt. On switchers with no engine or trailing truck, guidance had to come from the first and last driving axles, which had as little lateral play as was feasible (but there was always some, between the axle/frame fit and the flange gauge/rail gauge differences). This was mighty poor guidance, though, and was a major reason why they couldn’t run fast at all. Even at low speed, more than one hogger has had one hunt itself onto the ground even when he was doing nothing wrong!
…Oh yes, I can imagine the smaller 0-4-0 engines must have been hunting all the way down the track and then every curve it came to probably tried to climb the rail. Wear must have be atrocious.
Modelcars question was answered nicely.
It was common place to have flangless drivers on two adjacent axles on engines with 10 or more drivers and a ridged frame. The drivers never hung completely off the track though. Some portion of the wheel stayed of the track. You have to remember that those long ridged wheelbase engines didn’t stray from the main too far. Even with lateral movement and flangeless drivers they didn’t make a tight radius. They also didn’t lube the track like the modern engines do. The oil on the track came from what was dripping from every journel and slide lubricator not to mention oily steam.
One other thing to mention. All engines hunt to some extent. The new computer controlled steerable trucks hunt to some extent as well.
Two fixed guages, one ID and one OD can’t be the same guage. There has to be some tolerance. If there is tolerance there is hunt.
On some engines there is even violent hunt. If you didn’t have a seat you got tossed around the cab from side to side so you sat down on the plates or hung on for dear life.
Say, take care,
Sooblue