The article by Mr Zierke seems to be incorrect with regard to tilting and subsequent opportunity for higher speeds on existing "curvy" lines. Such sharp curves as a 1.000 foot radius are infrequent on most mainlines except in mountains..
Most European tilting trains, which would include both the Talgo and the Fiat-Siemens Pendolino DB Type 610, allow up to only 8 degrees, about 7.9 inches, of cant deficiency. This works out to only 55 mph for a 1,000 foot radius curve with 4 inch cant. Curiously, the equivalent cant deficiency is very close to the 11.8 inches presented as only the cant deficiency which may be a cause for error.
The EMD F59 locomotive used for the Cascade Talgo is the limiting factor cleared for only 7 inches cant deficiency, and this seems consistent with the higher limits on BNSF. The speed for a Cascade Talgo works out to 53 mph instead of 48 mph for a 1,000 foot curve radius and 4 inches cant.
Curiously, the 53 mph given for a non-tilting TGV coincides with the Cascade Talgo; and 6.9 inches of cant deficiency more likely would spill drinks and cause things to slide off tables and seat trays. The 48 mph given for Talgo works out to 4.9 inches cant deficiency which is more consistent with the NEC allowance for conventional, non-tilting trains, and is similar to pre-TGV SNCF practices for premium, all-reserved seat trains.
I'd be surprised if all Class I railroads didn't have detailed property drawings or computerized data marking the exact locations of curves and transitions. Furthermore, all the track charts I've ever seen, not just a schematic drawing, show curve degree and cant.
jeatonThe IC's track on its 99MPH territory from Champaign to Centralia was in relatively poor shape just because they didn't have the funds to keep maintenance of way up to what would have been best.
I realize old memories are often inaccurate. However, my recollection of riding various IC trains in the 60's from Champaign to Chicago was that whether their old coaches (on the student holiday specials) or streamlined cars on the CNO or COM, those trains rode very smoothly at 90+. I think the deterioration set in in the late 60's: poor maintenance + much heavier freight cars, so that by 1978 the slower ride was pretty rough. Ditto on the old NYC, 1958 vs 1976.
C&NW, CA&E, MILW, CGW and IC fan
schlimm jeaton In the few years before Amtrak, I frequently rode IC passenger trains legally operating at 99MPH and in those days, IC track in in their cab signal territory certainly did not class 6. But I wonder if that was, in part, because the average freight car was much lighter 40+ years ago and thus tracks could be maintained less expensively?
jeaton In the few years before Amtrak, I frequently rode IC passenger trains legally operating at 99MPH and in those days, IC track in in their cab signal territory certainly did not class 6.
But I wonder if that was, in part, because the average freight car was much lighter 40+ years ago and thus tracks could be maintained less expensively?
Not really anything to do with the issue. The IC's track on its 99MPH territory from Champaign to Centralia was in relatively poor shape just because they didn't have the funds to keep maintenance of way up to what would have been best. If I am not mistaken, that predated the FRA's formal track standards and speed limits. My point was that passenger trains were operated at 99MPH on track that was no better than today's current Class 5 standards with its 90MPH speed limit.
My question is from a track condition only, is it really necessary to have track at Class 6 for safe operation at 110MPH?
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jeatonI looked at some parts of the piece. While the techinical facts may be good, I sensed that the whys and wherefores might be arguable. A thought I have had about 90MPH as the limit for fully integrated service. As I see it there are three issues on the speed limits-signals, dispatching (the fast train, slow train mix) and track. Not coincidentally, 90MPH is the limit for passenger on class 5 track. Going to 110 MPH currently requires Class 6 for passenger. While Class 6 lets the freight railroads get an additional 10MPH, as I understand it, the possible benefit from somewhat faster freight service is far outweighed by the jump in cost to upgrade from Class 5 and maintain the track at Class 6. I have wonder whether the setting of the track standards and speed limits were somewhat arbitrary at the 5 and above level. In the few years before Amtrak, I frequently rode IC passenger trains legally operating at 99MPH and in those days, IC track in in their cab signal territory certainly did not class 6. (And maybe not even Class 5). Perhaps there were were engineering sttudies on the subject, but I wonder if the studies were back up with actual experimentation.
I looked at some parts of the piece. While the techinical facts may be good, I sensed that the whys and wherefores might be arguable.
A thought I have had about 90MPH as the limit for fully integrated service. As I see it there are three issues on the speed limits-signals, dispatching (the fast train, slow train mix) and track. Not coincidentally, 90MPH is the limit for passenger on class 5 track. Going to 110 MPH currently requires Class 6 for passenger. While Class 6 lets the freight railroads get an additional 10MPH, as I understand it, the possible benefit from somewhat faster freight service is far outweighed by the jump in cost to upgrade from Class 5 and maintain the track at Class 6.
I have wonder whether the setting of the track standards and speed limits were somewhat arbitrary at the 5 and above level. In the few years before Amtrak, I frequently rode IC passenger trains legally operating at 99MPH and in those days, IC track in in their cab signal territory certainly did not class 6. (And maybe not even Class 5). Perhaps there were were engineering sttudies on the subject, but I wonder if the studies were back up with actual experimentation.
If the frt traffic is light, you can fully mix, even up to 110 mph in many cases (ala CSX's Hudson Line and Amtrak's NEC). If it's heavy with frt, you pretty much need a separate track.
Elsewhere, YMMV. I can see the NCRR doing 90 mph with the mix of NS freight on the line. You could even do 100Hz carrier cab signal at a reasonable cost since NS's frt loco fleet is already equipped.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
I'm no technical expert, but wouldn't a limiting factor on shared track here vs. Europe be the much higher freight car axle loading weights here that require a heavier-duty roadbed and much higher maintenance? Wouldn't it be much like the exponential effect of semi's vs. autos on highway wear and tear?
I didn't particularly care for the assertion that US frt RRs aren't doing high speed freight because their mgt lacks vision and/or is too worried about next quarters financials. I just don't see that as a significant factor. I see the niche as too small for the cost to occupy it.
However, it really brings together the whys and wherefores of the current approaches:
- fully integrated passenger - up to 90 mph
- separate track, integrated operations - up to 110mph
- fully separate operation - new ROW
Searching for information about curve radii on mainline routes, I came across this technically detailed Web site
http://zierke.com/shasta_route/
authored by Hans-Joachim Zierke.
Besides the wealth of information about axle loads, cant deficiency, tilting technology, and FRA waivers, the site offers interesting insights into the differences between freight operations in the US and Europe and how this came to be. The claim is that the transcontinental routes in the US play the role of sea-borne freight routes in Europe, accounting for the heavy-slow vs lighter-faster freight trains between the US and Europe, and this factor needs to be taken into account in running passenger trains on freight lines.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
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