Good train handling is always a plus, but passengers generally seem to dislike rough handling a great deal more than most freight.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
ndbprr Given equal legnth freight and passenger trains is there a difference in the operating them as far as acceleration, hill climbing and descending, braking, etc.?
Dave H. Painted side goes up. My website : wnbranch.com
Freight train may well be considerably heavier, unless it is mostly empties, as passenger equipment is generally roughly equal in weight to an empty freight car, even when fully loaded with passengers.
Aside from that - and also a concurrent result of it, too - passenger trains are usually assigned a higher power-to-weight ratio (horsepower per trailing ton), so they will accelerate faster and climb grades faster than freight trains. The same considerations mean that a passenger train can usually descend a grade faster than a freight without risking a runaway from brake shoe fade, etc.
Finally, most passenger train air lines are set for 105 or 110 psi, whereas the standard freight train pressure is 90 psi.* That means the passenger train can make more of a 'reduction' = harder brake application before the reservoirs equalize with the brake pipe (see: http://www.alkrug.vcn.com/rrfacts/brakes.htm#pressurevariation ). So, passenger trains can go somewhat faster closer right up to stops and speed restrictions, etc., thus resulting in faster over-the-road time than an equal length (and even an equal weight) freight train.
*See: http://www.railway-technical.com/brake2.shtml - "3. Air Pressure Variations" at the bottom of the page.
"Air Brake Pressure on Amtrak Trains Using Freight Power" at: http://www.trainorders.com/discussion/read.php?4,2422482
http://www.sdrm.org/history/timeline/amatic.html
Rule 100.6 on page 6 of: http://www.blet75.org/2013-05-01_abth_updated.pdf
- Paul North.
There are a few differences as far as air brakes go. I'm not a locomotive engineer so these are both very simplified:
All bets are off when you're talking about historic equipment, whether passenger or freight. I've worked for a railroad that runs passenger trains at 70 psi with a manually-lapped brake system in the cab...
Yes.
He means air AND dynamics if the locomotives are dynamic equiipped. This is true both for freight and passengers, although my observation is that a more blended approach is used on passenger trains, while on frieght, the effort is to keep the slack (much greater on a freight, even of equal length) bunchd, using mainly the dynamic with variations contrrolled by the air brake used gently. In addition to less slack because of tighter coupling, commuter trains often have electric apply and release (both mu electric, and push-pull diesel and electric) in addition to train-line air control, and this means that all brakes apply and release at close to the same time, where as brakes on a freigh train with power only at the head end release and apply in sequence, approximately 1040 feet/second front-to-back.
TrainManTyAll bets are off when you're talking about historic equipment, whether passenger or freight. I've worked for a railroad that runs passenger trains at 70 psi with a manually-lapped brake system in the cab...
Ninety pounds, but ditto on the brakes (NYC RS3)... Manual transition, too, but that's a different thread.
Engines used by Amtrak, and maybe some of the commuter lines, have a system called, "blended brakes." It combines dynamics and air brakes with one control. I don't really know much more than that, except I've heard it really makes train handling easier. Passenger equipment is generally also equipped for graduated release. The brakes can be partially released so the engineer can reduce the amount of braking effort on the train. Conventional freight equipment can only be fully released, no partial release. (ECP brakes would be able to have a graduated release, but other than test trains I haven't heard of there use in the US yet. Actually haven't really heard much about ECP braking at all lately.)
I've had Amtrak detours and company business car trains. All have been with a freight engine (The detours because of ATC/cab signal requirement.) with the air brakes set up for freight service, even if the engines have the passenger option. The last passenger train I had was company equipment, and we always have a officer riding in the cab, even if it's just deadheading equipment. He told me not use dynamics, only air, and that I didn't have to "clean up" the air brake application. (In freight service they want at least a 10 psi set, unless you will be using the brakes again real soon. The Minimum service position on the brake valve only takes off 6 to 8 psi, usually requiring one to "clean up" by increasing the application.) I ran them the way he wanted, fully understanding that the next officer probably would want it ran a different way. (Interestingly, they don't assign anyone to ride with us on Amtrak detours. I've had 3 and only once did the Amtrak engineer ride up front. That was more to just see the scenery or maybe to give advice should he think a freight engineer needed it. He never said anything to me so I must have been doing it OK.)
The following link is about Amtrak detours from 2010. On the third page is a description of the first detour I ever had. Previously, my only passenger experience had been on the B&SV at 10mph.
http://cs.trains.com/trn/f/111/t/168135.aspx?sort=ASC&pi332=3
The second link is a youtube clip of one of the detours (guess who was running it) going through Grand Mound, IA.
http://www.youtube.com/watch?v=rkCHgh6pWPo
Jeff
It should be noted that the latest mu and electric locomotive equipment have a blend of air, dynamic, and regnerative brakiing, where braking current generated by the motors can be returned to the catenary or third rail if the load by other trains or train on the section is available and not just dissapaited in resistors. Some of the latest electrifications even have storage substations, using batteries or flywheels. In Europe, this is true of electric freight locomotives, not just passenger.
Paul_D_North_Jr Freight train may well be considerably heavier, unless it is mostly empties, as passenger equipment is generally roughly equal in weight to an empty freight car, even when fully loaded with passengers. - Paul North.
I don't doubt that this is true now, but was it when most (or all) passenger cars were what we now call "heavyweight" cars? I have always been under the impression that a heavyweight Pullman, empty or loaded, was about as heavy and offered similar rolling resistance as two or even three freight cars.
ChuckAllen, TX
There were 100-car freight trains during WWII. A single loaded coal hopper can weigh more than a heavyweight Pullman. Ditto an ore gondola. And the N&W ran 80-car coal trains.
Not all freight cars were 40-ton boxcars or refers.
cefinkjr Paul_D_North_Jr Freight train may well be considerably heavier, unless it is mostly empties, as passenger equipment is generally roughly equal in weight to an empty freight car, even when fully loaded with passengers. - Paul North. I don't doubt that this is true now, but was it when most (or all) passenger cars were what we now call "heavyweight" cars? I have always been under the impression that a heavyweight Pullman, empty or loaded, was about as heavy and offered similar rolling resistance as two or even three freight cars.
Back in the day -
Heavyweight passenger cars were considered to be 80 tons.Lightweight passenger cars were considered to be 60 tons.
In the days of wood cars with steel underframes they had a lightweight of 20 tons.All steel cars had lightweights between 25 & 30 tons.
The nominal loads for freight cars were between 50 & 70 tons + the lightweight of the car.
Never too old to have a happy childhood!
I think the 100-ton coal-carrying car goes back to WWII. With the light-weight, that would be 120-130 tons.
daveklepper I think the 100-ton coal-carrying car goes back to WWII. With the light-weight, that would be 120-130 tons.
Dave,
You are partially correct and partially incorrect.
There were a few major coal hauling railroads, the Norfolk & Western and the Virginian are two of them, that operated oversized 90-100 ton capacity gondolas (with 6 wheeled trucks in N&W's case) and hoppers even before the second World War but they were not the industry standard.
I know in the 40's and 50's many coal haulers (L&N for one) used 70 ton coal cars and IINM there were still many 45 ton cars in operation.
100 ton capacity didn't become the norm until the 1960's.
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
From The Virginian Railway (Kalmbach 1961):
... the railway placed orders in 1916 and 1917 with [four different builders] for the four classes of G–50000–3 experimental 120–ton gondolas.
and
They weighed 82,600, 83,300, 87,800, and 73,900, respectively, and were regarded as lightweights when originally built.
Good. Excpt for the 45-ton, loaded, all are heavier than a heavyweight Pullman.
daveklepper Good. Excpt for the 45-ton, loaded, all are heavier than a heavyweight Pullman.
I'm assuming you're replying to my last post, Dave. If so:
Right but these "battleship" gondolas were way outside the norm throughout the Golden Years of heavyweight passenger cars. They were only used, as far as I know, by VGN and N&W (or did C&O have some?). On both the VGN and the N&W, they were only a small part of those roads' coal carrying fleet. The vast majority were 50-ton hoppers. The large number of 40- to 50-ton gondolas used has always surprised me, too.
Curve and grade territory in mixed traffic often require track construction that puts one mode at a disadvantage to the other, most commonly with spirals and crosslevel in curves. ATSF & DRGW used to give speed (passenger) the priority over tonnage(freight). In some locations, curve rail had a very short life.
Three miles east of La Junta on ATSF is a curve that used to have 6 inches of crosslevel in it to maintain 70 mph train speed, Great for Amthrax, but low speed coal drags just starting out of the yard after refueling would eat the low rail alive. Flange lubricators only created more headaches (and whining trainmasters/ road foremen) for getting the train started and the ties soaked-up any excess fuel dripping from the filler neck or the sump. (instant gage problem with soft ties and rectangular spike holes)....now Amthrax slows down a tad [50 mph] and the ties and rail last longer.
Setting up the territory's track structure has an effect on operating characteristics for passenger/freight. On curves, you want the wheels contacting both rails evenly, just slightly favoring one side or the other.
mudchickenCurve and grade territory in mixed traffic often require track construction that puts one mode at a disadvantage to the other...
There are spots on our line that haven't been rebuilt yet that still have pretty impressive superelevation. The Central used to run the line at up to 50 MPH. While we run 40 MPH is spots, our "locals" keep it down to 25 MPH for the most part, and one section is currently at 15 MPH. We've had trouble with our gensets on a couple of curves there if the oil wasn't right up to the full mark on the stick.
Of course, we aren't running the traffic ATSF or anyone else did/does on their mains, so that 1925 105Lb Dudley will probably last a while...
Right,, but but the light weight of the 50-ton hopper was 25 ton, making 75 in total, just 5 tons short of a hecavywight Pullman. Long passsnger train = 30 cars, all heavyweights -= 2400 tons. Long freight = 100 cars, all loaded 50-ton hoppers = 7500 tons. Short pasenger train = 3 cars = 240 tons. Short freight = 10 cars = 750 tons. Generally, freight trains are heavier than passenger.
Previous post assumes all 30 car heavyweight trains were all-Pullman. Stillwell Erie coaches weighed 44tons, NY-Westchester-and-Boston 75-foot mu cars weighted 55 tone witih their electrical equipment, and most convetional four-wheeled-truck standard coaches wieghed 55-60 tons, such as the PRR P-70.
A three car passenger train could be a total-service passenger train: mail-baggage-express or mail-baggage-express-combine, coach, Pullman buffet-sleeper. That is sort of the minimum total-service train. I guess one could shorten it to two cars, with all coach passengers in the combine.
tree68 mudchickenCurve and grade territory in mixed traffic often require track construction that puts one mode at a disadvantage to the other... There are spots on our line that haven't been rebuilt yet that still have pretty impressive superelevation. The Central used to run the line at up to 50 MPH. While we run 40 MPH is spots, our "locals" keep it down to 25 MPH for the most part, and one section is currently at 15 MPH. We've had trouble with our gensets on a couple of curves there if the oil wasn't right up to the full mark on the stick. Of course, we aren't running the traffic ATSF or anyone else did/does on their mains, so that 1925 105Lb Dudley will probably last a while...
The big difference is freight does not complain and passengers do!!
rbandr The big difference is freight does not complain and passengers do!!
Freight may not complain but the Shippers/Receivers will!
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