I'm fairly certain this was a rare occurance on any road.
It does beg the question 'Is this ok? Things will work? Now this is just a switcher so perhaps not a big deal but I'm not sure you could do this with a road unit... or could you?
I know FM had a B truck and a A1A truck on some early C Liners but that's factory and things were engineeered that way.
So could a railroad just swap out trucks with totally different characteristics on one end than the other?
7041 with mismatched trucks! Original Blunt type on rear and more modern so-called AAR type. Digital restoration Gordon Kennedy
Not a big deal mechanically as long as the motors were of the same type and gearing. EMD switcher trucks were also interchangeable. There's a photo in one of the "Diesel Spotter's Guide" editions of a K&IT SW1500 with one AAR and one Flexicoil truck. AAR B trucks used on road switchers weren't quite as easy to substitute for Blombergs since the motor ratings and gearing would be a mismatch. Rock Island put Blombergs under re-engined FAs, and Soo put Baldwin AAR Type Bs under Alco RSC2s and an RSC3. The Baldwin trucks kept their Westinghouse motors.
Blunts were considered high-maintenance, which might explain the use of cast AAR trucks as available.
Great information and history, thanks rcdrye and NDG.
First: the use of B-A1A on the FM 2000 and 2400hp cabs was for reasons of weight distribution - note that you still have four traction motors, unlike the "BoCo" locomotives in Britain. Similar reasoning for the arrangement on FL9s.
It's possible that there were mismatches on road units, but I suspect it would be rare and temporary, so photographic evidence might be very slight (and records that would prove the practice even more scanty). You'd need similar centerpin and side-bearing provisions (these were usually builder-specific; when locomotives were delivered with 'trade-in' trucks the frames would have been configured properly for them) and spring capacity and weight, as well as the wheel and gearing issues described.
It would be particularly rare to have a road (or component) failure that would involve a complete truck swap, rather than dropping an involved motor/gearcase unit for replacement. On switchers, especially older ones with nonstandard parts and relatively low-revenue use, swapping trucks to save bucks is reasonable. I'd think road units would tend to be switched to 'one or the other' if for no other reason than to standardize expected maintenance.
Thank You.
Weren't the FL9s an example of mixed trucks?
My recollection is that the first two units were outshopped with two axle Flexicoils at the front, matching the three axle Flexicoils at the rear.
The lead trucks were changed to Blombergs, and the rest of the class were built that way.
Since the trucks were different to start with, it is less obvious that they started out with trucks with the same suspension arrangements front and rear and ended up with different arrangements.
But the trucks were interchanged.
Peter
Never happened, and scrapped.
FL9s
M636CMy recollection is that the first two units were outshopped with two axle Flexicoils at the front, matching the three axle Flexicoils at the rear. The lead trucks were changed to Blombergs, and the rest of the class were built that way.
Blombergs? Swing-hanger Blombergs with third-rail beams???
Please send me some of that stuff you've been smokin'. I believe you have it exactly backward: the two prototypes were built with Blomberg lead trucks (with the third-rail shoes somewhat dysfunctionally attached to the trailing-truck Flexicoil between its first and second axle -- this being one significant reason to use a Flexicoil sideframe on a passenger engine in the first place) and this was quickly revised to lead-truck Flexicoil to be able to put leading shoes where they belonged.
Certainly I don't remember seeing any FL9 operating with a Blomberg truck, and none of the surviving examples have them -- see for instance
The first two prototype FL9s were built with Blombergs with no third rail shoes. The B Flexicoils used for the production FL9s (and retrofitted to the prototypes) had a 108" wheelbase, the switcher flexicoil had a 96" wheelbase. The rear truck on the FL9 was an A1A flexicoil, all other three axle flexicoils were Cs.
Indeed I had it reversed....
The FL-9s started with mismatched trucks but changed to matched trucks....
But the point is valid. The trucks arrived mismatched.
I think I've seen a photo of an F unit Demonstrator (not FL-9) with a flexicoil truck at both ends....not mismatched, and it may have been related to testing prior to the FL-9 production.
There is no difference between an A1A Flexicoil truck and a C Flexicoil truck apart from whether there is a motor on the middle axle. I think all Flexicoils were cast with the nose suspension point for the middle motor. Trailing axles were often not braked, so the brake gear could differ.
While there were no other A1A Flexicoils in the USA, there were 11 locomotives in Australia that had A1A Flexicoils both ends, and quite a few in Europe. In Europe the choice was between six D19/D29 narrow gauge motors or four D22/D32 standard gauge motors on basically the same locomotive. Norway had mainly units with six small motors but picked up three demonstrators with four big motors.
The last of the 11 1951 built Australian units with A1A trucks (loco GM-10) still working is now running with trucks cast in 1964 that used to have motors on the middle axle. In fact the middle axles still have drive gears (no motor, but the gears are there). Last I looked, this unit still had a 567BC engine with rectangular inspection covers. I have no idea if the power assemblies are still 567s since you cant tell from outside.
I realise I may have invited a rush of commentary from Canada, since G8 and G12 export units were used in Canada. Some of these had distinctive fabricated Flexicoil A1A trucks with a 120" wheelbase and a 36" whelset as the idler axle. These were also used in New Zealand and in Queensland on G12 units. In Queensland these were arranged to have 15 tons on the driving axles and 9 tons on the idler axles. I think some of the Canadian trucks had the idler axle removed, but those in Queensland and New Zealand did not.
The Australian (standard and broad gauge) Flexicoils had a wheelbase 12" less than the US domestic trucks but were basically symmetrical. There were also standard export Flexicoils that were significantly shorter than the Australian trucks (maybe another 12") and were decidedly assymetrical. These were known as "GLC" trucks and were applied to SDL 39s, but were relatively rare on standard gauge in Australia.
M636CBut the point is valid. The trucks arrived mismatched.
Perhaps a more interesting point: since the (far inferior to A-1-A "Blomberg") Flexicoil on the rear was specified mainly to accommodate the shoe beam, why was the rear truck not made swing-hanger when the lead truck was made Flexicoil? That would preserve the 'original intent' of the mismatch but now 'in reverse'...
Peter, can you be a bit more specific on the 'demonstrator' with two Flexicoils? Does this mean you have a picture with no shoe beam on the lead truck but the 'original' one on the trailer? The Blombergs on the two first units were replaced comparatively fast (I think Mr. Klepper may know when) and I'd think the replacements would have shoe beams and buss arrangements quickly if not 'as installed'
FL9s were originally expected to operate in pairs with a 600 volt bus. This was quickly found to be impractical, as was the original idea of using a single third rail shoe per side.
rcdryeFL9s were originally expected to operate in pairs with a 600 volt bus. This was quickly found to be impractical, as was the original idea of using a single third rail shoe per side.
Another place for a useful scholarly article I would avidly read is the whole long and lamentable history of building dual-mode equipment for third-rail electrifications, most of it involving the NYC approach to GCT. If there was a version of lightweight Train Of The Future that actually got this to work without halting and catching fire, I'd like to know it; certainly not even the TurboTrain figured out more than a "half-acid" (family-friendly chemistry allusion) approach to reasonable running.
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