No 21 is reported nearly 4.5 hours late for Temple, TX today, June 28th. It has averaged 3.2 hours late for the past five days. Amtrak claims it is due speed restrictions caused by heat and weather.
I believe the maximum speed for Nos. 21 and 22 between Fort Worth and Temple is 79 mph. When they must slow down because of heat restrictions, what would be the maximum allowable speed?
I don’t know UP or BNSF implementation of Heat Orders. On CSX, Heat Orders when issued are in effect from 1300 to 1900 and reduce speeds of freight trains by 10 mph, but not lower than 30 mph, and to reduce the speed of passenger trains by 20 mph, but not lower than 40 mph.
Amtrak has a red banner near the top of its webpage that reads: High temperatures may require trains to operate at lower speeds. The latest banner is dated July 7th. It gives the time the lower speeds may be in effect, but it does not say which routes are impacted by the lower speed limits. The banner has been on the page, if my memory serves me correctly, for three or more weeks.
What is the trigger temperature that results in implementation of the reduced speeds?
Presumably some or maybe all passenger trains on BNSF, UP, NS, etc. would be impacted by reduced speeds. Would the same restrictions apply to the NEC?
If passenger trains have to reduce speed because of high temperatures, what does this say about the viability of high-speed trains in the face of climate warming?
Nominally 90 degrees F is the trigger temperature for Heat Orders. Steel responds to temperature - not the individual carrier, with that being said not all carriers anchor their track structures in the same manner. Individual carriers have their own triggers and know their own physical plants and their rail installation temperatures, which has an effect on how much rail expansion can be expected with any given temperature.
On CSX rail is laid at different temperatures depending upon the states the rail is installed in. North Carolina, Tennessee and South 100 degrees is the normalized installation temperature. Virginia is 95 degrees and the remaining Northern part of the railroad is 90 degrees.
On a 100 foot length of track at 25 degree increase in RAIL temperature will have the rail ‘grow’ 1/4 inch. In welded rail installations, the rail can be miles long in its installed welded condition. The quarter inch per 1
Don’t know where but once read that various Amtrak track sections have different high heat restrictions. As well CAT has different values so sometimes CAT might be limiting and other times track might be limiting.
UP has two levels of Heat restrictions. Level 1 doesn’t affect passenger trains. Level 2 would slow them to 50 mph.
There can be additional local restrictions (usually on unsignalled track, especially branch lines) and sometimes lower speeds can be issued by track bulletin during the times a heat restriction is in place.
Jeff
Spain and Saudi Arabia both have high-speed lines…
When speed is the primary concern and you have lighter trains a railroad’s track construction and maintenance practices may be handled differently than what the North American Class I’s do, since they are focused on tonnage and cost-cutting at the ‘expense’ of increased unreliability and slower speeds.
Have viewed pictures of some really wavy tracks from accross the pond. Heat will find the weak point of everyone’s track structure.
Heat wasn’t as much of a problem in the days of stick rail as each bolted up rail joint allowed a small degree of movement within the nature of the bolted joints and expansion/contraction was exerted on each of the thousands of joints. With stick rail nominally being 39 feet in length and expansion being on the order of 1/4 inch per 100 feet - that required at least 4 joints within that 100 foot span as it took 2+ rails per 100 feet.
LGV and other HSR-specific track can have active elements to maintain correct rail alignment. One version looks like facing switchpoints constrained against the gauge side.
These solutions might not be considered cost-effective for slower-peak-speed service.
See also the device called a ‘breather switch’.
What is not understood is that the country of India has solved the problem of rail expansion. That country Has instaslled what appeaars to be miter rasils on their welded rail which seems to work very well. Do not have a picture of exactly what the actual expansion joint is like. Of course not invented here>?
I am not so sure India runs their railroads to turn a profit. My limited observations make is seem that Indian railroads are a major employer in the country and their purpose is to create jobs for the Indian population.
Everything has a cost.
Hate to say it but I think you are colliding with inertia, aka, “Old Thinking” both here and on the railroad.
Just for tangental discussion:
Indian State railways slightly larger than BNSF employs 1.2 million people.
BNSF employs 64,000 employees.
Forget the ton-mile comparisons but BNSF carries a lot more tonnage, in fact I think I remember it was exponentially more tonnage. Granted India State Railways carries more passengers which is more people intensive but are passenger trains really that people intensive?
In 2022–23, Indian States Railways operated 8,479 trains on average daily and transported 1418 million tons of freight of freight. BNSF reports ton-miles, so not comparable.
Apparently my post about the ‘breather switch’ got lost in some of the 504 activity.
Here is a conference paper from 2016 that describes the approach:
I can imagine one of those speaking on the radio:
“Whew! glad that train passed over me without derailing!”.[:D]
Approximations using other stats in combo?[:D]
Lets start, a ton mile is one ton carried one mile.
Indian railways runs 9146 frieght trains daily (start with that).