I have noticed that passenger trains seem to use a high number of locomotives for relatively short trains. Besides the obvious advantages of having backup power available in case of a failure is there a reason railroads do this? It certainly doesn’t take 3 P-42’s to pull a 15 car train.
Part of it is providing HEP (head-end power). IIRC Amtrak’s rule of thumb is one engine for every five cars. Remember everything in the passenger cars works from the engine’s electrical power - lights, A/C, heat, ovens in the dining car, etc.
Part of it is the power diverted to heat and light the passenger cars, about 800 hp. the rest is to run at higher speeds on the grades that will be encountered. BNSF will be satisfied climbing Stevens Pass in Washington State at 10 mph, Amtrak wants to climb the same grade at 25 to 30 mph where the curves will allow that speed. To achieve the higher speed requires a much higher power to weight ratio, and remember that 800 hp has been diverted for train utilities. Amtrak likes to have about 6 hp per trailing ton on the western trains, the most important BNSF Intermodal trains get about 4 hp per trailing ton, drag freights and unit trains may have 1 hp per ton or a bit less.Time is less important to freight than cost.
For example on the Soo Line’s flat River Subdivision a 4400 hp AC4400CW is rated to handle 11,000 tons or 2.5 tons per hp. or another way 0.4 hp per ton.
Another reason is that freight locos are geared for top speed about 70MPH. All P-42s and the P-40s that are being rebuilt are geared for 110 MPH. This higher speed gearing takes more HP for acceleration and climbing hills than freight locos. This is so that all locos can be used on any route. the only exception is some locos still don’t have cab signaling / ATS for operating on all RRs. The P-40s are getting that installed during overhaul.
All P40’s and P42’s came with cabsignal/atc and the ATSF type trainstop right from factory.
Whats being installed now is either ACSES or the Michican type PTC something like ITC …
Horsepower also equals acceleration from stops and speed restrictions. Its all about power to weight ratio for passenger service. One P42 may very well have enough power to keep the train at track speed on a particular route, but it isn’t going to get the train up to speed as fast as two additional units will.
Passenger operations and freight operations are two different animals.
Speed kills. In more ways than one.
A person’s time is valuable. And that person will pay to save his/her valuable time. A load of coffee doesn’t need to save those hours. That’s why the best rail freight time from Chicago to LA was/is around 50 hours while the best passenger time was 39.5 hours. The Santa Fe could, and did with the “Super C”, put freight over the route in less than 40 hours. They found out there wasn’t much of a market for doing that expensive thing.
To move passenger trains at their higher speeds simply requires more power. That’s an expense and the determining factor is whether the expense can be covered by what is charged to the customer. One reason long distance passenger trains are hopelessly uneconomic is that you can’t charge enough to cover the cost of running them at the necessary higher speeds. Aircraft do it more efficiently and save much more time.
The best example comes from the Sea-Land SL-7 class container ships. These vessels could flat out move. They could sustain about 33 knots and legend is that the first Atlantic crossing of a SL-7 was intentionally slowed down so as not to ebarrass Cunard with their then new QE2. (Didn’t want the cargo ship beating the time of a new passenger liner.)
The SL-7s almost destroyed Sea-Land. They couldn’t charge enough to cover the cost of providing the extra speed. Container ships move around the world at about 22 - 23 knots and anything more than that is a waste of money. Sea-Land escaped its very big mistake by unloading the SL-7s to the Department of Defense which keeps the ships in reserve to move heavy Army units (think tanks) to where they may need to go. (Kind of a 1970’s era bail out.)
So anyway, Amtrak trains have a lot of power so they can run fast. This helps make them money loosers. A 40 MPH terminal to terminal intermodal freight schedule will do just fine and get the vast m
I have always heard that Amtrak’s rule of thumb is one engine for every seven cars. That may work on most LD trains, but what about the Auto Train? It has two engines and 16 cars.
I’ve heard of something like that too. In the early 2000s I remembered seeing mainly one P42 on either the Silver Meteor or Silver Star trains followed by 11-13 passenger cars. Two engines were only common on the Auto Train and the Sunset Limited, but I did see two engines on the Silver Meteor one time in 2001 I believe. I wonder why they run two engines now. I think the rules changed or something like that.
The Auto Train makes only a single stop for a crew change, The Silver Star and Silver Meteor make multiple stops and so need better acceleration. You will find that even with their stops the Star and Meteor cover the same distance in less time. In the West two units are the minimum, three for the Southwest Chief over Raton and Glorieta Passes. Two locomotives can get the Chief over the passes only by cutting off the power to the rest of the train proactively (before they start up the grade) and both units better be in good condition.
IIRC, the majority of the cost of running an LD passenger train is labor, not fuel. There is a trade-off in reducing labor costs by running the train faster and the increased morive power and fuel costs, but I’d suspect that the cross-over point is higher than what is achievable on most lines in the US. The ROW, track and signaling could be upgraded to permit higher speeds, but the traffic would not come close to justifying the costs involved.
FWIW, the Iowa class ships needed 212,000 HP to reach 33 knots (about 3.5 HP/ton), where a train could easily beat 33 knots (38 MPH) with 1HP/ton.
- Erik
It has discussed the extra HP as being a waste of resources. But twice the HP on a given train is not twice as costly.
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Crew time (Engineer & Conductor) either being able to make a longer run or not on duty so long as to go on overtime. That saves on total number of crews and the overhead of benefits.
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For a given run you will not need twice as many locos since the trains can complete the runs faster by accelerating faster and climbing hills faster.
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As an example BNSF intermodal haulage trains with 3 locos accelerate much faster out of our siding than same length UPs with 2 locos. (approximately same length)
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Fuel consumption is greater with higher speeds as doubling speed should require 4 times the fuel.
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Per diem / car hire ==. Especially intermodals almost all trains use TTX cars (however BNSF does use some of their own ) which I believe are subject to an hourly charge?. But BNSF would not need as many of their own or get as many TTXs) So if your operation requires X number of cars at a lower speed then you only require maybe 2/3X cars at a higher speed?
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Fluidity is important,. The occasional slow train for whatever reason really gums up the works and so all trains that can maintain a good speed is important.
I wonder what would be the cost factors for rail travel if railways were maintained by the government, as are U.S. and Interstate highways? Truck/bus/airline travel is to/from federal-maintained airports, or upon federal-maintained roads and highways. Taxes and fees imposed are insufficient to cover upkeep. The railroads still are being forced to do their own road maintenance, AND pay fees, yet other transportation is subsidized ! Small wonder rail isn’t cheaper than air travel !
This subject has been beat to death a few times here. You can find lots of stuff doing a search. The results may not be as pleasing as you might like. The bottom line is that once you take the user fees (ticket tax and fuel taxes) into account, the subsidy per passenger mile for air is pretty low - cents on the dollar. The subsidy for Amtrak is around 50% for the long distance trains. Acela more than covers operating costs, but not all the capital. Other NEC trains come close to covering operating cost but don’t contribute much of anything to capital. Driving on an interstate results in autos subsidizing the trucks. All the other factors are just nibbling around the edges.
And yet, European countries are able to subsidize their rail systems with other-than-auto fuel taxes, I believe, keeping rail travel costs lower. European autos travel MUCH less distances than the U.S., and as fuel is very costly, their average MPG is higher to use LESS fuel, so tax revenues MUST come from elsewhere. Also, European rail coverage is much better, area-wise, than the U.S., except perhaps the Northeast.
Oh sure.
Once you turn a train into a hotel with beds, a restaurant, and a lounge it gets real expensive. (Labor cost.) But in my own defense I didn’t say the cost of the extra power made the LD passenger trains money loosers, I said the cost of the extra power helped make them money loosers. And it does.
The Iowas were 1940’s technology and powered with steam. If I understand correctly there are two of them still on the Navy’s reserve roster and the Navy hates that. Congress will not allow the last two Iowas to be put to sleep. Container ships move around the world at about 67% of the speed the Iowas could do. The reason these container ships, almost 70 years later, don’t go faster is not because the technology is not avaialble. The reason the modern
[quote user=“greyhounds”]
erikem:
greyhounds:
So anyway, Amtrak trains have a lot of power so they can run fast. This helps make them money loosers. A 40 MPH terminal to terminal intermodal freight schedule will do just fine and get the vast majority of the freight off the highway. A 40 MPH passenger schedule is a dud.
IIRC, the majority of the cost of running an LD passenger train is labor, not fuel. There is a trade-off in reducing labor costs by running the train faster and the increased morive power and fuel costs, but I’d suspect that the cross-over point is higher than what is achievable on most lines in the US. The ROW, track and signaling could be upgraded to permit higher speeds, but the traffic would not come close to justifying the costs involved.
FWIW, the Iowa class ships needed 212,000 HP to reach 33 knots (about 3.5 HP/ton), where a train could easily beat 33 knots (38 MPH) with 1HP/ton.
- Erik
Oh sure.
Once you turn a train into a hotel with beds, a restaurant, and a lounge it gets real expensive. (Labor cost.) But in my own defense I didn’t say the cost of the extra power made the LD passenger trains money loosers, I said the cost of the extra power helped make them money loosers. And it does.
The Iowas were 1940’s technology and powered with steam. If I understand correctly there are two of them still on the Navy’s reserve roster and the Navy hates that. Congress will not allow the last two Iowas to be put to sleep. Container ships move around the world at about 67% of the speed the Iowas could do. The
I brought up the example of the Iowa’s as they had the same top speed as the SL-7’s and thus should have similar power to weight ratios (weight for the ship, not the machinery). The Nimitz class carriers also have about the same top speed, but I don’t have their weight and power memorized as well as I do for the Iowa’s. The main point is that ships are less fuel efficient than trains when speeds go above 20 or so MPH. The issue with ships is that wave drag gets out of hand when approaching hull speed, whereas the drag rise for freight trains starts at a much higher speed.
Your comment about the Concord SST is valid, the nature of Mach 2.2 flight makes it far less fuel efficient than flying at Mach 0.8. On the other hand, you also don’t see much desire to further improve efficiency by dropping speed to Mach 0.6.
- Erik
There are times when nothing does beat a 16inch Rifle hitting a bunker on the beach. Trust me Iran would Not be doiung half the crap they are doing NOW if we parked one of the Iowas in the Persian Gulf think of the Damage she could do just to the Docks for the Fleet or to the anything in range for 16inch guns. Then throw in her Longerrang stuff and you have a big problem. The thing is when we bring a Carrier into te Gulf they can not manuver and have to be closely gaurded.
…We are way off topic here but the 16 inch gun issue is the “bring back steam” argument of many military discussion forums I visit. Why anyone would think in 2010 that a salvo of 16 inch shells is scarier to a potential enemy than 2000 lb. GPS guided JDAM smart bombs raining down from the sky or a wave of Tomahawk land attack missiles fired from submarine or surface vessels is a little beyond me…
And don’t get me wrong,I love Battleships, I pass the USS Massachusetts many days on my way to work and the USS Wisconsin (Iowa class) was in mothballs near where I live up until very recently…