ChessieCat123Isnt the Canadian LRC Design based on the British APT or Advanced Passenger Train?
In my opinion, not really. There may be some overlap and 'inspiration' from what BR was doing with the theory of tilt in the '60s, but the Canadians appear to have made a real effort to do as much of a "invented-in-Canada" approach as possible.
The 'basic' idea of what became the LRC was a relatively low, stiff structure in aluminum, with good underbody streamlining and reduced gaps between cars and around trucks. The tilt mechanism is very different from what Kit Spackman et al. developed, I think in part because the Canadian loading gauge allows more clearance for the carbody at maximum tilt than the British does. It uses rollers and lateral hydraulic actuation, which produces more a roll around a neutral axis (probably near average seated head height) rather than a pivot point up high (as in the suspended pendular suspension, like Talgo) or down low (as with the jacks in the APTs).
I suspect one major reason why the tilt was deactivated (and I think after 2007 progressively removed with associated further weight saving) was that it was hydraulic and likely depended on something in the special locomotives to power it. If I understand correctly each car has its own gyroscopic system for tilt, and would need something like the APT's coordinated-curve system to run at true high speed (but I understand that even in the Toronto-Montreal corridor there was desire to limit superelevation for freight-related reasons, so the tilt was designed just for 'normal' high speed of under 110 mph).
The 'evolution' as I understand it is from LRC to Acela to Voyager on the Bombardier side, and APT to Pendolino on the other. Someone here can probably comment better on the actual physics of tilt to reduce perceived lateral force by passengers; I'm not an expert in the field, but I have greatly enjoyed the ability to communicate directly with the surviving APT designers and technicians.
Paul MilenkovicYa quoted me out-of-contex
I did not mean to be critical (or imply that you didn't know the vehicle dynamics of tilt vs. non-tilt). Just thought I would mention a couple of points that general forum readers might not have thought about.
Wizlish Paul Milenkovic The LRC locomotive was supposed to be light weight, but as its horsepower grew between prototype and production version, its weight grew to just short of the 120 tons typical for a four-axle diesel. Hence it could never realize the full benefit of active tilt. It might be appropriate to mention here that the LRC locomotives themselves did not have active tilt, and that in any case active tilt compromises, rather than helping, both vehicle running stability and lateral rail forces, so there is little point in putting it on pure locomotives. I am not sure how far the lower apparent CG of the LRC locomotive actually helped with stability (perhaps someone who knows can comment on the FM Speed Merchant locomotives, which also had relatively high powerplant size and mass constraints (an FM OP is a relatively tall engine, and it features a whole crankshaft and associated structures up at the top end). Certainly a lower engine with heavy weight and relatively primitive (by modern standards) truck design is going to have significant lateral thrust effects, and this is what would keep the LRCs with that power from 'realizing the full benefit of active tilt' -- not a limitation in what the tilt system could or did accomplish. BTW - there may be something interesting about the construction or suspension of the LRC locomotive's traction motors. I asked the folks at the Toronto museum that has one restored to running condition, but they did not know at the time what the differences were. Does someone here know?
Paul Milenkovic The LRC locomotive was supposed to be light weight, but as its horsepower grew between prototype and production version, its weight grew to just short of the 120 tons typical for a four-axle diesel. Hence it could never realize the full benefit of active tilt.
It might be appropriate to mention here that the LRC locomotives themselves did not have active tilt, and that in any case active tilt compromises, rather than helping, both vehicle running stability and lateral rail forces, so there is little point in putting it on pure locomotives. I am not sure how far the lower apparent CG of the LRC locomotive actually helped with stability (perhaps someone who knows can comment on the FM Speed Merchant locomotives, which also had relatively high powerplant size and mass constraints (an FM OP is a relatively tall engine, and it features a whole crankshaft and associated structures up at the top end). Certainly a lower engine with heavy weight and relatively primitive (by modern standards) truck design is going to have significant lateral thrust effects, and this is what would keep the LRCs with that power from 'realizing the full benefit of active tilt' -- not a limitation in what the tilt system could or did accomplish.
BTW - there may be something interesting about the construction or suspension of the LRC locomotive's traction motors. I asked the folks at the Toronto museum that has one restored to running condition, but they did not know at the time what the differences were. Does someone here know?
Ya quoted me out-of-context by leaving out my preceding sentence, "Unless you have light axle loads, you are limited by the speed around curves from the heavy locomotive spreading the rails."
The LRC locomotive was indeed supposed to be light in weight (the "L" in LRC stood for legere much as the "L" in Talgo stands for ligero), which at one time was to include a lightweight locomotive, but I guess it didn't work out that way. Weight budgets start out with the best of intentions . . .
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
NorthWest We had this discussion before, and never got down to the unique features that the GE 785 was supposed to have. The only new insight was that BBD's 1960 Class for Portugal also had them.
We had this discussion before, and never got down to the unique features that the GE 785 was supposed to have. The only new insight was that BBD's 1960 Class for Portugal also had them.
And some of those are still 'alive and well', but now they work for the freight sector. As these units don't have the electric complications of LRCs they're far more reliable, but not as powerfull. Here's a little vignette showing one of the units at work (with a cement train)
It should be remembered that the Acela trailer cars are basically just updated LRC trailer cars, and they are regarded as pretty much a commercial success. Bombardier had some time and years of VIA service to get the design right second time around for Amtrak.
You should also remember the Turboliners, both the French and Rohr versions and the UA Turbotrains both on Amtrak and VIA . These were all justifiable steps in moving from the 1940s "Heritage Fleet" to the present day with Acela and Amfleet cars.
The Amfleet was really just a conventional Budd sitting car using the expensively developed shell of the Metroliners, the latter which could be regarded as less successful than the LRC. But the Amfleet cars did everything the LRC trailers were expected to do at less cost with greater reliability and there isn't any great demand for them to be replaced yet, although they are running with their third or fourth generation of locomotives (dependng upon how you define an AEM-7AC).
Amtrak only ever leased the LRC from Bombardier and returned them when they decided that they didn't need them. I'd expect Bombardier took any losses involved. However, it gave both Amtrak and Bombardier experience that helped with the Acelas.
VIA still use their cars. The power cars were always more for show and F40PHs and P42s are just as good except for appearance.
M636C
Paul MilenkovicThe LRC locomotive was supposed to be light weight, but as its horsepower grew between prototype and production version, its weight grew to just short of the 120 tons typical for a four-axle diesel. Hence it could never realize the full benefit of active tilt.
Paul MilenkovicI also read that when the LRCs were set up to tilt the maximum amount, the passengers got seasick from the rolling of the passenger car with passage through curves being similar to a rolling ship. This was supposedly cured by limiting the LRCs to a partial tilt.
Are you sure this anecdote doesn't relate to the British APT?
The British efforts at high speed involved more sophisticated use of the tilting systems to run fast on very curving lines. According to a couple of the principal designers, at the introduction of one of the APT prototypes the 'representatives of the press' were a bit over-plyed with alcoholic beverages at BR expense, which materially contributed both to the 'seasickness' and to the ensuing negative press opinions.
As things turned out in that era, the much less complicated HST125s provided the level of service that was needed, without complicated active tilt, hydrokinetic braking, and the like. The additional market value of very high speeds on those typical lines -- including what we now know to involve much greater track maintenance concerns for only marginal time savings on most British service segments -- didn't justify the added cost and complexity.
I suspect also that much of the 'seasickness' involves passengers standing up or moving around while the active tilt is operating. At the roll rate required for cant-deficiency correction in full servo, it would be unsurprising to find many inner ears, even absent EtOH concerns or confused with visual 'sight references' through the windows, in difficulty under those conditions, if the system were correcting cant deficiency based on accelerations at seated head height...
My understanding is that, because of the tigihter track spacing, Acelas simply switch off tilt when on Metro North. And normal speed limits for curves apply. Acelas on Metro North do not operate faster than Amtrak Regionals or MN commuter trains.
All the different permutations of the LRC locomotive were at the least...problematic. HEP, traction motor blowers, etc.,etc....
CPM500
Actually, Amtrak had experience with tilt (pre Talgo) with the United Aircraft TurboTrains they inherited.
One of the selling points of the LRC is active tilt, which can tilt a large amount and tilt more quickly than passive tilt. Active tilt is where you have sensor and actuators to bank the train whereas passive tilt is the result of a "pendular" suspension where the train naturally banks in response to centrifugal force.
The amount of passive tilt on the Talgo is limited to no more than half the amount that would remove all of the "cant deficiency" (that is, that apparent sideways force on the passengers). On the other hand, passenger cars with "outside air springs" (Amfleet) exhibit less "wrongway tilt" resulting from body roll. Not tilting the wrong way as much merits FRA waivers for going faster around curves.
The other limitation on active tilt, apart from the expense of the rolling stock and its maintenance, is the locomotive. Unless you have light axle loads, you are limited by the speed around curves from the heavy locomotive spreading the rails.
The LRC locomotive was supposed to be light weight, but as its horsepower grew between prototype and production version, its weight grew to just short of the 120 tons typical for a four-axle diesel. Hence it could never realize the full benefit of active tilt.
I also read that when the LRCs where set up to tilt the maximum amount, the passengers got seasick from the rolling of the passenger car with passage through curves being similar to a rolling ship. This was supposedly cured by limiting the LRCs to a partial tilt. I also heard that Canada's LRCs are still in service with the tilt disconnected; does anyone know of the Bombardier Acela's have their tilt disconnected (owing to tighter clearances on Metro North), or do they just tilt a reduced amount?
The LRC trains gave Amtrak some experience with tilting carbodies - a good thing to have for the Shoreline. So, not a complete waste of time.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
The MLW 251 power was too oddball for what was then an EMD 567/645 world with Amthrax plus the all to common quality issues of the day.
Many years ago I took a distant slide of an AMTRAK LRC coming into New Haven being pulled by a Conrail locomotive. (I was in the old New Haven Railroad Yard) I assumed that the MLW locomotive had a failure enroute and they commondeered whatever was close to finish the run. I was visiting the area on my way to Maine for vacation so this was just a chance encounter. If what I saw occurred often enough I would have returned them too.
Not too advanced. Too uncomfortable. Was FORCED to ride one from Hammond-Whiting to Kalamazoo in the winter of 1983. It was cold and rough riding.
Mel Hazen; Jax, FL Ride Amtrak. It's the only way to fly!!!
Hello all ;
While searching for stuff about those tiny LRC canadian trains, I found something about the ones amtrak tested. Were they too advandced for amtrak then ?
Here are some links about such trains and cars ;
http://history.amtrak.com/blogs/blog/the-lrcs
http://www.railroad.net/forums/viewtopic.php?f=46&t=58496
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