I wonder if some of this has to do with the goal of 9in unbalanced vs the 7in the old acela was allowed.
Apparently it has more to do with behavior on straight track, on track that carries mixed traffic (with wheels with different profiles) - things like hunting etc.. The issue of rail and flange profile has been known as an issue since the days of Metroliner, but until they tried to operate regularly at above 150mph they could somehow keep things sufficiently under control and carry on. Still Acelas at 150 mph has a ride quality that no one would accept in Europe. They'd send out track equipment to fix the track, and yet Acelas operate day in and day out bouncing all over the place. This problem has to be solved if we expect to operate trains at 150+mph on mixed traffic trackage. Better to figure it out now rather than after something bad happens.I wonder if some of this has to do with the goal of 9in unbalanced vs the 7in the old acela was allowed.
Given how much of the NEC seems to have newer concrete rail ties in the fastest of sections (NB to Trenton), wouldn't logic say that the flange profile issues would have been resolved at some point over the last 50 years? Or can I read this post as saying this is the same rail that PRR laid down so many years ago with just some new concrete ties on it.Apparently it has more to do with behavior on straight track, on track that carries mixed traffic (with wheels with different profiles) - things like hunting etc.. The issue of rail and flange profile has been known as an issue since the days of Metroliner, but until they tried to operate regularly at above 150mph they could somehow keep things sufficiently under control and carry on. Still Acelas at 150 mph has a ride quality that no one would accept in Europe. They'd send out track equipment to fix the track, and yet Acelas operate day in and day out bouncing all over the place. This problem has to be solved if we expect to operate trains at 150+mph on mixed traffic trackage. Better to figure it out now rather than after something bad happens.
I am guessing to some extent reading between the lines, so I could be wrong. Maybe @George Harris has more informed insights on this matter, since he has been a practitioner, while mine is just bookish knowledge.
well i would think first the brightline train sets have already been tested and approved for use, while the avelia is a brand new train, even the siemens cars with all there issues where first used on brightline as well without many issues. the segment between Orlando and cocoa is brand new while the rest is upgraded freight tracks. i know even in Mansfield where the acela reaches 150 some of the rail dates back to the 80s not to mention other parts that might have rail from the 70s so if there was any advancement in the type of rail the new avelia requires its definitely not on the nec in any meaningful way.Not to get too off topic, but are any of these issues being noticed on Brightline's Orlando segment or not really? Sure they arent going 150mph on that, only 125 or 110, but seems like Brightline might inherit some of the same issues Amtrak has that comes with a mixed use railroad and using older track/ROW. Just curious if this is more of an Amtrak issue or just a US railroading issue everywhere. Or perhaps given the amount of construction required, Brightline properly replaced the potential causes of ride quality issues while Amtrak has not.
age doesn't really matter for rail so much as how worn it is. there is 75+ year old rail on 80mph segments on the west coast but because they have light traffic the rail is still in good condition.well i would think first the brightline train sets have already been tested and approved for use, while the avelia is a brand new train, even the siemens cars with all there issues where first used on brightline as well without many issues. the segment between Orlando and cocoa is brand new while the rest is upgraded freight tracks. i know even in Mansfield where the acela reaches 150 some of the rail dates back to the 80s not to mention other parts that might have rail from the 70s so if there was any advancement in the type of rail the new avelia requires its definitely not on the nec in any meaningful way.
Siemens has long figured that out, they likely used the ACS-64 to get a good 130-140mph wheel for mixed traffic lines here in the USNot to get too off topic, but are any of these issues being noticed on Brightline's Orlando segment or not really? Sure they arent going 150mph on that, only 125 or 110, but seems like Brightline might inherit some of the same issues Amtrak has that comes with a mixed use railroad and using older track/ROW. Just curious if this is more of an Amtrak issue or just a US railroading issue everywhere. Or perhaps given the amount of construction required, Brightline properly replaced the potential causes of ride quality issues while Amtrak has not.
Apparently regular precision grinding of rail heads also prolongs the life of rails and reduces the chances of fatigue failures. I don;t know the exact Physics of it, but it has to do something with micro fatigue cracks of the railhead being prevented from growing as a result of being ground out, or something like that.Age is of no real significance in rail. Rail life is based on wear and development of internal defects in the steel and is usually defined in million gross tons of traffic. Rail is ground regularly to deal with undesirable wear patterns and imperfections in head shape occurring under traffic. Rail is also regularly tested for internal defects in the steel. Rail steel is considerably harder than that used in steel beams. Current rail on the NEC is either 136RE, 141RE, or 140RE, that is weighing those many pounds per yard. I listed 140RE last deliberately as that is considered obsolete. This was originally a Pennsylvania design and many miles were installed in the NEC, so there may be quite a bit still there. "RE" is American Railway Engineering and Maintenance of Way design shape. These are actually the world's best in rail shapes. As rail wears, it is usually "cascaded" to lower speed lower traffic lines. Rail up to 100 years old can be found in minor tracks. Much of this older rail will be in lighter sections, down to as light as 90 lbs/yd. Rail is usually left in main tracks longer than in years past, an in the days of use of jointed rails, end batter and defects around the bolt holes usually defined when rail needed removal from high speed main tracks. Thes rails were usually cut back beyond the old joint bar holes and new holes drilled, and the rail placed in a lower density track. Frequently the process would be repeated once or more additional times.
In the late 1980's in Denver we found that what looked like a slightly lower elevation third track on the Joint Line was actually the main line of the Denver, South Park and Pacific narrow-gauge, with rails stamped as being from the 1890's. In a newer use in Denver, alert visitors on the Southeast LRT lines may find Pueblo-rolled rails stamped as having come from steel scrapped from old Mile High Stadium. Properly maintained, they should last longer than the stadium did.Age is of no real significance in rail. Rail life is based on wear and development of internal defects in the steel and is usually defined in million gross tons of traffic. Rail is ground regularly to deal with undesirable wear patterns and imperfections in head shape occurring under traffic. Rail is also regularly tested for internal defects in the steel. Rail steel is considerably harder than that used in steel beams. Current rail on the NEC is either 136RE, 141RE, or 140RE, that is weighing those many pounds per yard. I listed 140RE last deliberately as that is considered obsolete. This was originally a Pennsylvania design and many miles were installed in the NEC, so there may be quite a bit still there. "RE" is American Railway Engineering and Maintenance of Way design shape. These are actually the world's best in rail shapes. As rail wears, it is usually "cascaded" to lower speed lower traffic lines. Rail up to 100 years old can be found in minor tracks. Much of this older rail will be in lighter sections, down to as light as 90 lbs/yd. Rail is usually left in main tracks longer than in years past, an in the days of use of jointed rails, end batter and defects around the bolt holes usually defined when rail needed removal from high speed main tracks. Thes rails were usually cut back beyond the old joint bar holes and new holes drilled, and the rail placed in a lower density track. Frequently the process would be repeated once or more additional times.
Didn’t the PRR at one time have 155 pound rail? I believe it was the heaviest…Age is of no real significance in rail. Rail life is based on wear and development of internal defects in the steel and is usually defined in million gross tons of traffic. Rail is ground regularly to deal with undesirable wear patterns and imperfections in head shape occurring under traffic. Rail is also regularly tested for internal defects in the steel. Rail steel is considerably harder than that used in steel beams. Current rail on the NEC is either 136RE, 141RE, or 140RE, that is weighing those many pounds per yard. I listed 140RE last deliberately as that is considered obsolete. This was originally a Pennsylvania design and many miles were installed in the NEC, so there may be quite a bit still there. "RE" is American Railway Engineering and Maintenance of Way design shape. These are actually the world's best in rail shapes. As rail wears, it is usually "cascaded" to lower speed lower traffic lines. Rail up to 100 years old can be found in minor tracks. Much of this older rail will be in lighter sections, down to as light as 90 lbs/yd. Rail is usually left in main tracks longer than in years past, an in the days of use of jointed rails, end batter and defects around the bolt holes usually defined when rail needed removal from high speed main tracks. Thes rails were usually cut back beyond the old joint bar holes and new holes drilled, and the rail placed in a lower density track. Frequently the process would be repeated once or more additional times.
Passed by the Race Street yard on #43a few hours ago. One of the trainsets had multiple undercarriage doors open for an unknown reason. No workers present, though.
Yes, and yes.Didn’t the PRR at one time have 155 pound rail? I believe it was the heaviest…
Now that’s what I would call “high iron”, back when the PRR called itself, “The standard railroad of the world”.Yes, and yes.
The 155 lb section was a Pennsylvania Railroad standard section designed and adopted by them in 1946 as the 155PS. It was a slight revision of an older 152 lb/yd PS section. The 155PS was last produced sometime earlier than 1963. I understand that there was quite a bit in several of the heaviest used Pennsy tracks, including the NEC. So far as I know, all has long since disappeared from the northeast corridor, and probably everywhere else, as well. Apparently it was a step too far so far as track stiffness was concerned.
The 155PS section was HUGE: 8 inches high with a 6 3/4 inch wide base and a 3 inch wide head.
There are heavier rails, but they are designed and used to support rail mounted cranes. So far as i know they have never been used in railroad service.
I'm rather amused that no one commented on one of the trainsets being moved to Boston last week and back to Philly the next day.
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