7j43kA commuter coach might weigh 80 tons. A locomotive might weigh twice that. So the effect would be as if the rear pushing loco was replaced by two cars. Doesn't seem like much difference.
The difference is in the concentration of the weight on the axles, the effect on braking, and to a lesser extent on the difference in draft gear between the cars in the train and the locomotive.
When pushing, the slack runs in and out relative to the location of the locomotive, with the effect possibly delayed up to several seconds. This could be pronounced at the cab end in some of the latter-day Hudson Line trains with FL9s, where very perceptible 'nudges' were common with throttle changes and surges could be observed when braking to a stop.
I suspect better blended braking solves some of the issues.
At the time of the Glendale accident, there was talk about this. Thinking further, maybe it was just talk:
A commuter coach might weigh 80 tons. A locomotive might weigh twice that. So the effect would be as if the rear pushing loco was replaced by two cars. Doesn't seem like much difference.
Ed
7j43k York1 I don't know enough about how trains operate to comment. Is there any difference in starting and stopping when pushing as opposed to pulling? Any slack between cars cause a difference? Other issues? Another issue is having the momentum of a locomotive compressing the train when the front of the train hits an impediment. The Metrolink Glendale crash of 2005 might be a good example. Ed
York1 I don't know enough about how trains operate to comment. Is there any difference in starting and stopping when pushing as opposed to pulling? Any slack between cars cause a difference? Other issues?
I don't know enough about how trains operate to comment.
Is there any difference in starting and stopping when pushing as opposed to pulling? Any slack between cars cause a difference? Other issues?
Another issue is having the momentum of a locomotive compressing the train when the front of the train hits an impediment. The Metrolink Glendale crash of 2005 might be a good example.
7j43k Another issue is having the momentum of a locomotive compressing the train when the front of the train hits an impediment. The Metrolink Glendale crash of 2005 might be a good example. Ed
I didn't go through all the posts to see if this was answered, but I think you're seeing the Keystone trains to Harrisburg which run "push-pull."
In the 1990's, Amtrak operated the "Pennsylvanian" as a Chicago-Philadelphia day train with a large amount of mail & express in express boxcars and RoadRailers. It usually ran about 20 cars and departed from Track 28/19. During the Christmas season, the tail end of the train would extend to under Madison Street.
Based on the Rwy Age drawing, the longest CUS platforms were just about a quarter-mile -- so fifteen postwar cars.
zardozI bet the commuters just love trying to find their way in the dark. Don't the doors close when the power goes off? I know they did on the old CNW bi-level coaches. We were forbidden to cut power once boarding began--not even to use 'standby' on the locomotive.
Yes, I remember that also from before the turn of the century. But have not noticed the doors closing when the HEP is cut. The "emergency" lights do come on in the cars and so people are not in total darkness.
charlie hebdoBack in the day before Amtrak and cutbacks in service, I thought some PRR and CB&Q trains were longer than 11 cars? Did they have to break the train in half?
No. Tracks 18 through 26 (South side tracks are even numbers) have longer platforms and those are used by Amtrak and could hold longer (20 car) trains and extend out into the interlocking plant. GM&O's were not the long ones but PRR and BN did have some long trains that extended out toward Harrison Street past the interlocking tower. If you scroll down about halfway in the following article about CUS, there is a diagram of the track layout from when it was built.
https://chicagology.com/skyscrapers/skyscrapers044/
You can see that the West tracks have shorter platforms. And the commuter trains use the eight west platforms. (Note that track 2 is under Canal Street)
I don't know how other routes did it, but on the Southwest Service, the changeover from station power to HEP is made about five minutes before train time. It usually takes only about a minute or so and lights and power are restored well before departure time. Regular riders are familiar with the process and barely fazed by it.
Electroliner 1935 Now when the train arrives in the station and while passengers are in the process of getting off, the HEP goes off and then about two minutes later, the Shore Power comes on. The locomotive is put on idle speed. And similarly, when departing, the conductor closes the doors, the Shore power is cut, and the passengers sit in the dark (with the emergency lights on) for about a minute, then you can hear the locomotive rev up, the train starts to move and in about thirty seconds the HEP comes on, Lights and HVAC blowers come on.
nhrandIn the old days, the steam era for example, trains running backwards had a lower speed limit than trains running normally. I think this was partly due to the visual problems but maybe due to less reliable tracking. Today, do cars running in a long train with a powerful locomotive pushing in the rear have any tracking issues ??
Push-pull is only used in passenger operations. Steam engines could not be controled in the manner that diesels are in push-pull operations.
Each freight carrier has their own set of train handling rules that govern how to shove large cuts of cars.
Never too old to have a happy childhood!
In the old days, the steam era for example, trains running backwards had a lower speed limit than trains running normally. I think this was partly due to the visual problems but maybe due to less reliable tracking. Today, do cars running in a long train with a powerful locomotive pushing in the rear have any tracking issues ??
charlie hebdo Electroliner 1935 Metra BNSF trains have gotten about as long as they can and still fit on the eight station tracks (even 2-16) allocated to Metra . The Naperville express trains run eleven cars long and most trains have six or more cars. The Naperville trains make three stops inbound (start at Aurora, Rt 59, & Naperville) and then run non-stop to Chicago carrying about 1500-1600 passengers. Back in the day before Amtrak and cutbacks in service, I thought some PRR and CB&Q trains were longer than 11 cars? Did they have to break the train in half?
Electroliner 1935 Metra BNSF trains have gotten about as long as they can and still fit on the eight station tracks (even 2-16) allocated to Metra . The Naperville express trains run eleven cars long and most trains have six or more cars. The Naperville trains make three stops inbound (start at Aurora, Rt 59, & Naperville) and then run non-stop to Chicago carrying about 1500-1600 passengers.
Back in the day before Amtrak and cutbacks in service, I thought some PRR and CB&Q trains were longer than 11 cars? Did they have to break the train in half?
My personal observations from 'back in the day' - the end of those trains were out in the open air beyond the platforms.
Electroliner 1935Metra BNSF trains have gotten about as long as they can and still fit on the eight station tracks (even 2-16) allocated to Metra . The Naperville express trains run eleven cars long and most trains have six or more cars. The Naperville trains make three stops inbound (start at Aurora, Rt 59, & Naperville) and then run non-stop to Chicago carrying about 1500-1600 passengers.
The Talgos in the Pacific Northwest are also push-pulls, using demotored F40PH's as control cabs.
LIRR ran push-pulls in the 1980's, with GP38-2's or MP15AC's for motive power and demotored (but not de-engined) FA's and F's to provide HEP and control cabs.
GO Transit in Toronto is Push-Pull (Photos 1, 2, & 3)......and AMT (now EXO) in Montreal is also Push-Pull (Photos 4, 5, & 6)
Part of the pollution problem (exhaust fumes in trains) was a result of the failure of the owner of the former Chicago US Postal Service Building to maintain the exhaust ducts and blowers that removed the fumes from the track area of Union Station. And the Tier 1 locomotives having to run at approximately 900 RPM to maintain HEP service to the train put out a lot of exhaust. After the pollution issue arose, Metra started putting trains that were not doing a quick flip, onto shore power. This requires additional manpower to plug and unplug the power cables. And there is a specific protocol for the transition. Now when the train arrives in the station and while passengers are in the process of getting off, the HEP goes off and then about two minutes later, the Shore Power comes on. The locomotive is put on idle speed. And similarly, when departing, the conductor closes the doors, the Shore power is cut, and the passengers sit in the dark (with the emergency lights on) for about a minute, then you can hear the locomotive rev up, the train starts to move and in about thirty seconds the HEP comes on, Lights and HVAC blowers come on. We are on our way. Also, when we pull out of Union Station, the exhaust that is spewed out of the locomotives that have been idling is confined to the train area under the air-rights building and into the passenger car air intakes. Not much of a problem for the Ogilvie (former C&NW) and LaSalle St Stations which have open areas over the tracks and the exhaust can lift up and away.
Also Balt, the Metra BNSF trains have gotten about as long as they can and still fit on the eight station tracks (even 2-16) allocated to Metra . The Naperville express trains run eleven cars long and most trains have six or more cars. The Naperville trains make three stops inbound (start at Aurora, Rt 59, & Naperville) and then run non-stop to Chicago carrying about 1500-1600 passengers.
At Union Station - considering the 'relatively' short METRA and Amtrak trains, aren't the locomotives generally idling underneath the platform cover with less than ideal natural veltilation?
zardoz charlie hebdo As a fan/bystander, I still liked those Es and Fs better than anything since. Heck, I even liked the old Geeps and the rare SD7. On the plus side, with those locomotives one could actually repair malfunctions; on the minus side, they needed those repairs quite frequently. Kind of like the old days when you could see the ground when you looked in the engine compartment, or you could force the carburetor to stay open with a screwdriver. With these new cars, I don't even bother to carry tools--what is fixable roadside? The E8&9's were my favorite suburban locomotives: they rode nice and were good performers. (Just don't ask me about those Crandallized units!) charlie hebdo The Trib article was just a few years ago and referred to the current engines - F40PHs. Now that does surprise me! ================================================ F40 cab view of Lake Street Interlocking in Chicago:https://www.flickr.com/photos/jim53171/8028258253/ F7 cab view: https://www.flickr.com/photos/jim53171/8028221619/
charlie hebdo As a fan/bystander, I still liked those Es and Fs better than anything since. Heck, I even liked the old Geeps and the rare SD7.
On the plus side, with those locomotives one could actually repair malfunctions; on the minus side, they needed those repairs quite frequently. Kind of like the old days when you could see the ground when you looked in the engine compartment, or you could force the carburetor to stay open with a screwdriver. With these new cars, I don't even bother to carry tools--what is fixable roadside?
The E8&9's were my favorite suburban locomotives: they rode nice and were good performers. (Just don't ask me about those Crandallized units!)
charlie hebdo The Trib article was just a few years ago and referred to the current engines - F40PHs.
Now that does surprise me!
================================================
F40 cab view of Lake Street Interlocking in Chicago:https://www.flickr.com/photos/jim53171/8028258253/
F7 cab view: https://www.flickr.com/photos/jim53171/8028221619/
The Trib ran it also, but it has a paywall.
https://news.medill.northwestern.edu/chicago/union-station-faces-air-pollution-issue-epa-says/
Feb. 2016:
assengers on trains at Chicago’s Union Station are being exposed to high levels of air pollution on Metra and Amtrak trains, according to the U.S. Environmental Protection Agency.
Over a two-week period in July 2015, EPA researchers used portable aerosol monitors to measure microscopic particles in the air around the train platforms and streets surrounding the station, said John Mooney, an air quality expert at the EPA in Chicago.
The particles, known as PM2.5, or particulate matter about 2.5 micrometers in diameter, are composed of liquid droplets and acids, metals, or other pollutants in the environment. PM2.5 are a byproduct of diesel-burning engines used in older trains such as the ones at Union Station., 225 S. Canal St.
“We expected average levels to be lower. They were higher than we like to see,” Mooney said. [As high as 299 ppm at rush hour.]
One thing I failed to mention on the Piedmonts is that the seating has been converted to half facing in each direction in each coach. Obviously you can guess which seats fill up first, though personally I don't mind riding backwards.
Deleted due to computer hicup.
charlie hebdoAs a fan/bystander, I still liked those Es and Fs better than anything since. Heck, I even liked the old Geeps and the rare SD7.
charlie hebdoThe Trib article was just a few years ago and referred to the current engines - F40PHs.
blue streak 1 matthewsaggie The NC Piedmont trains are running pull-pull, but being converted to push-pull as additional de-motered locomotoves arrive to serve as control cabs. That is probably wise because of the many grade crossing in NC and the many crossing accidents that have occurred!
matthewsaggie The NC Piedmont trains are running pull-pull, but being converted to push-pull as additional de-motered locomotoves arrive to serve as control cabs.
The NC Piedmont trains are running pull-pull, but being converted to push-pull as additional de-motered locomotoves arrive to serve as control cabs.
That is probably wise because of the many grade crossing in NC and the many crossing accidents that have occurred!
The cabcars I operated had the Engineer's cubbyhole on the top deck, so most collisions would be below me, although not so if I hit a truck; luckily I never did.
zardoz charlie hebdo Even so, carbon and other emissions were very high, as the Tribune exposed a few years ago. Perhaps in part a function of very old engines? Back when the CNW part of Metra was still using the F7 and E8's, those locomotives would sit at idle while awaiting departure; they also had an auxillary Cummins (and briefly a few had Detroit) HEP engines in the rear. Those engines, even though they operated at a high RPM, were nasty, smelly, and oily. So between the low-revving prime mover and the awful HEP motors, it's not too surprising that the air quality was terrible.
charlie hebdo Even so, carbon and other emissions were very high, as the Tribune exposed a few years ago. Perhaps in part a function of very old engines?
Back when the CNW part of Metra was still using the F7 and E8's, those locomotives would sit at idle while awaiting departure; they also had an auxillary Cummins (and briefly a few had Detroit) HEP engines in the rear. Those engines, even though they operated at a high RPM, were nasty, smelly, and oily. So between the low-revving prime mover and the awful HEP motors, it's not too surprising that the air quality was terrible.
As a fan/bystander, I still liked those Es and Fs better than anything since. Heck, I even liked the old Geeps and the rare SD7.
The Trib article was just a few years ago and referred to the current engines - F40PHs.
Johnny
The Keystone Service trains make sense but the Amtraks I have seen going backwards are definitely running north between PHL 30th St. and NYP. I actually dont think they can turn a train around in Philly or they would have been turning the Atlantic City Trains frontward for all these years.
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