2 Engines

[Nathanael]

I guess the limit for gradeless trains is about 7 cars. Those trains you mentioned all exceed that, while gradeless trains below that all have only one locomotive. The Palmetto now runs with only one locomotive.

Gotcha. Makes perfect sense. Thanks!

 

[xyzzy]

The southbound Crescent has a long sustained grade leaving Toccoa, Ga. Roughly 7 miles of 1.5%, with curves. Track conditions are often damp because of local micro-climate. Would be a slow slog with a single locomotive.

Most difficult grade (other than the Hudson River) for the Palmetto, Carolinian, Silver Star, and Silver Meteor is Franconia hill south of Alexandria, Va.; but it doesn't last long. Although the ex-ACL is relatively flat, the ex-SAL used by the Silver Star traverses rolling hills between Raleigh and Columbia. Two P42's are helpful to maintain schedule on the Star, although frankly the schedule has so much slop in it now that I'm not sure it matters. CSX just wants to keep the ex-ACL fluid in case of an engine failure.

Under normal circumstances the Palmetto, Carolinian, and Piedmonts run with a single locomotive.

 

[George Harris]

It is not just power to haul. Given horsepoer per ton, any passenger train could make it over the line with only one engine. Look at what you see on the front of a freight train. However, it would accelerate very slowly and would not be able to keep speed up on the grades.

As to why idle for lengthy periods: Start up and shut down of a large diessel engine is not as simple as turning the key in your car. Fuel consumption at idle is very low, so unless the shutdown period will be very long it is better to leave it at idle.

Empire Builder: The west approach to the Cascade Tunnel has about 10 miles of 2.20% grade and the east approach has about 6 miles of 2.20% grade, and there are several miles of lesser grades in approach to each of these. The tunnel itself is on a 1.70% grade, up eastbound.

 

[Swadian Hardcore]

The southbound Crescent has a long sustained grade leaving Toccoa, Ga. Roughly 7 miles of 1.5%, with curves. Track conditions are often damp because of local micro-climate. Would be a slow slog with a single locomotive.

Most difficult grade (other than the Hudson River) for the Palmetto, Carolinian, Silver Star, and Silver Meteor is Franconia hill south of Alexandria, Va.; but it doesn't last long. Although the ex-ACL is relatively flat, the ex-SAL used by the Silver Star traverses rolling hills between Raleigh and Columbia. Two P42's are helpful to maintain schedule on the Star, although frankly the schedule has so much slop in it now that I'm not sure it matters. CSX just wants to keep the ex-ACL fluid in case of an engine failure.

Under normal circumstances the Palmetto, Carolinian, and Piedmonts run with a single locomotive.

I just checked up on that Toccoa grade on a contour map. Yeah, that would require some extra power. Now I wish Amtrak would cut some padding.

It is not just power to haul. Given horsepoer per ton, any passenger train could make it over the line with only one engine. Look at what you see on the front of a freight train. However, it would accelerate very slowly and would not be able to keep speed up on the grades.

As to why idle for lengthy periods: Start up and shut down of a large diessel engine is not as simple as turning the key in your car. Fuel consumption at idle is very low, so unless the shutdown period will be very long it is better to leave it at idle.

Empire Builder: The west approach to the Cascade Tunnel has about 10 miles of 2.20% grade and the east approach has about 6 miles of 2.20% grade, and there are several miles of lesser grades in approach to each of these. The tunnel itself is on a 1.70% grade, up eastbound.

I heard that locomotives aren't thst hard to shut down, but once you turn it off there will be tons of leaks, wasting even more fuel than if left on idle.

 

[NW cannonball]

Freight on the flat are often dispatched with about 1 horsepower per ton. But they don't have to go very fast, don't need much acceleration.

Amtrak runs with at least 8 horsepower per ton - sometimes 12, mostly for acceleration after the many station stops.

Another technical point about freight vs passenger on the long haul Amtrak routes - possibly some dispatchers just don't know how fast Amtrak LD trains can get up to speed.

It's not just average speed, it's how fast the train can get to next siding.

But about having 2 engines -- on the long-distance routes it's mostly about not having one engine failure leave a train blocking the main. That would have the dispatchers running for their supervisors in short order.

The freights never have less than 2 engines, just so in case one fails - blocking the main is - total revenue loser.

 

[Swadian Hardcore]

Freight on the flat are often dispatched with about 1 horsepower per ton. But they don't have to go very fast, don't need much acceleration.

Amtrak runs with at least 8 horsepower per ton - sometimes 12, mostly for acceleration after the many station stops.

Another technical point about freight vs passenger on the long haul Amtrak routes - possibly some dispatchers just don't know how fast Amtrak LD trains can get up to speed.

It's not just average speed, it's how fast the train can get to next siding.

But about having 2 engines -- on the long-distance routes it's mostly about not having one engine failure leave a train blocking the main. That would have the dispatchers running for their supervisors in short order.

The freights never have less than 2 engines, just so in case one fails - blocking the main is - total revenue loser.

Why didn't they build the P42DC with two smaller engines? Seems more efficient to me.

 

[Shortline]

The southbound Crescent has a long sustained grade leaving Toccoa, Ga. Roughly 7 miles of 1.5%, with curves. Track conditions are often damp because of local micro-climate. Would be a slow slog with a single locomotive.

Most difficult grade (other than the Hudson River) for the Palmetto, Carolinian, Silver Star, and Silver Meteor is Franconia hill south of Alexandria, Va.; but it doesn't last long. Although the ex-ACL is relatively flat, the ex-SAL used by the Silver Star traverses rolling hills between Raleigh and Columbia. Two P42's are helpful to maintain schedule on the Star, although frankly the schedule has so much slop in it now that I'm not sure it matters. CSX just wants to keep the ex-ACL fluid in case of an engine failure.

Under normal circumstances the Palmetto, Carolinian, and Piedmonts run with a single locomotive.

I just checked up on that Toccoa grade on a contour map. Yeah, that would require some extra power. Now I wish Amtrak would cut some padding.

It is not just power to haul. Given horsepoer per ton, any passenger train could make it over the line with only one engine. Look at what you see on the front of a freight train. However, it would accelerate very slowly and would not be able to keep speed up on the grades.

As to why idle for lengthy periods: Start up and shut down of a large diessel engine is not as simple as turning the key in your car. Fuel consumption at idle is very low, so unless the shutdown period will be very long it is better to leave it at idle.

Empire Builder: The west approach to the Cascade Tunnel has about 10 miles of 2.20% grade and the east approach has about 6 miles of 2.20% grade, and there are several miles of lesser grades in approach to each of these. The tunnel itself is on a 1.70% grade, up eastbound.

I heard that locomotives aren't thst hard to shut down, but once you turn it off there will be tons of leaks, wasting even more fuel than if left on idle.

Not true, maybe it was back in the 50's but today's diesels are almost as simple as your car to start and stop. In fact, many now utilize "smart start" technology, to shut diesels down when idling for a certain period of time, and start them back up when air pressure drops, temps fall close to freezing, or the power is needed. It's a little more complicated than that, but not much.

 

[Shortline]

Freight on the flat are often dispatched with about 1 horsepower per ton. But they don't have to go very fast, don't need much acceleration.

Amtrak runs with at least 8 horsepower per ton - sometimes 12, mostly for acceleration after the many station stops.

Another technical point about freight vs passenger on the long haul Amtrak routes - possibly some dispatchers just don't know how fast Amtrak LD trains can get up to speed.

It's not just average speed, it's how fast the train can get to next siding.

But about having 2 engines -- on the long-distance routes it's mostly about not having one engine failure leave a train blocking the main. That would have the dispatchers running for their supervisors in short order.

The freights never have less than 2 engines, just so in case one fails - blocking the main is - total revenue loser.

Why didn't they build the P42DC with two smaller engines? Seems more efficient to me.

It would be a bit more complex than that. Some new hybrid switchers do just that, but it hasn't worked out yet for road engines. Main reason is cost and maintenance-you would need two starters, two cooling systems, two oil systems, two main generators etc etc etc

 

[AlanB]

Freight on the flat are often dispatched with about 1 horsepower per ton. But they don't have to go very fast, don't need much acceleration.

Amtrak runs with at least 8 horsepower per ton - sometimes 12, mostly for acceleration after the many station stops.

Another technical point about freight vs passenger on the long haul Amtrak routes - possibly some dispatchers just don't know how fast Amtrak LD trains can get up to speed.

It's not just average speed, it's how fast the train can get to next siding.

But about having 2 engines -- on the long-distance routes it's mostly about not having one engine failure leave a train blocking the main. That would have the dispatchers running for their supervisors in short order.

The freights never have less than 2 engines, just so in case one fails - blocking the main is - total revenue loser.

Why didn't they build the P42DC with two smaller engines? Seems more efficient to me.

It would be a bit more complex than that. Some new hybrid switchers do just that, but it hasn't worked out yet for road engines. Main reason is cost and maintenance-you would need two starters, two cooling systems, two oil systems, two main generators etc etc etc

While I admit up front that this engine has an additional purpose over say a P42, and it could be argued that they are so new that it might be too early to say that it has "worked out"; NJT & Montreal do indeed have road units that have 2 engines within, as well as the ability to draw from overhead catenary. There is a more NJT specific data sheet which I can't find right now; but here's the Bombardier sheet for the entire family.

 

[xyzzy]

Cost is one reason why the P42's have a single prime mover. It's not just the purchase cost of two big-dollar components, but the maintenance cost. Although GMD E units featured internal redundancy, they were also expensive to maintain because there were more things to break.

But another reason on the P42's is length, which has a limit.

 

[George Harris]

Freight on the flat are often dispatched with about 1 horsepower per ton. But they don't have to go very fast, don't need much acceleration.

Amtrak runs with at least 8 horsepower per ton - sometimes 12, mostly for acceleration after the many station stops.

Another technical point about freight vs passenger on the long haul Amtrak routes - possibly some dispatchers just don't know how fast Amtrak LD trains can get up to speed.

It's not just average speed, it's how fast the train can get to next siding.

But about having 2 engines -- on the long-distance routes it's mostly about not having one engine failure leave a train blocking the main. That would have the dispatchers running for their supervisors in short order.

The freights never have less than 2 engines, just so in case one fails - blocking the main is - total revenue loser.

Freights do run quite commonly with 1 unit. It is just that normally on main lines the idea is to have as heavy a train as the terrain and sidings will permit. If for any of many reasons the train tonnage falls under the tonnage allowance for a single unit, the train will get a single unit.

 

[xyzzy]

Maybe, maybe not. If there is time-sensitive freight (intermodals, etc) on a line that is operating at or near capacity, a railroad might be reluctant to dispatch a freight with a single unit no matter how light the train is.

 

[Nathanael]

The "Water Level Route" taken by the Lake Shore Limited -- which really has no significant grades IIRC -- is the one I am most interested in. What's the motivation for dual engines from Albany to Chicago? Is it simply the sheer length of the train? Or is it for redundancy in case of engine failure? If it's simply the length of the train, there starts to be a sound argument for doubling the frequency.

 

[jis]

The "Water Level Route" taken by the Lake Shore Limited -- which really has no significant grades IIRC -- is the one I am most interested in. What's the motivation for dual engines from Albany to Chicago? Is it simply the sheer length of the train? Or is it for redundancy in case of engine failure? If it's simply the length of the train, there starts to be a sound argument for doubling the frequency.

Not really. Two trains cost more to operate than one for various reasons.

 

[Swadian Hardcore]

Freight on the flat are often dispatched with about 1 horsepower per ton. But they don't have to go very fast, don't need much acceleration.

Amtrak runs with at least 8 horsepower per ton - sometimes 12, mostly for acceleration after the many station stops.

Another technical point about freight vs passenger on the long haul Amtrak routes - possibly some dispatchers just don't know how fast Amtrak LD trains can get up to speed.

It's not just average speed, it's how fast the train can get to next siding.

But about having 2 engines -- on the long-distance routes it's mostly about not having one engine failure leave a train blocking the main. That would have the dispatchers running for their supervisors in short order.

The freights never have less than 2 engines, just so in case one fails - blocking the main is - total revenue loser.

Why didn't they build the P42DC with two smaller engines? Seems more efficient to me.

It would be a bit more complex than that. Some new hybrid switchers do just that, but it hasn't worked out yet for road engines. Main reason is cost and maintenance-you would need two starters, two cooling systems, two oil systems, two main generators etc etc etc

I don't know how hard it actually is, but the old E-units had two prime movers. I guess it's much harder in a monocoque locomotive.

The "Water Level Route" taken by the Lake Shore Limited -- which really has no significant grades IIRC -- is the one I am most interested in. What's the motivation for dual engines from Albany to Chicago? Is it simply the sheer length of the train? Or is it for redundancy in case of engine failure? If it's simply the length of the train, there starts to be a sound argument for doubling the frequency.

I think that one engine could handle the LSL, but it's so long the acceleration would be horrible. Maybe it could work out if many stops were cut.

 

[Shortline]

True, the E units did have more than one prime mover, but, they were relatively short lived, and are gone-Just wasn't cost beneficial. To fix one, you still lose the entire engine. Might as well have two separate units. Of course, nothing in this world is new, heck, I'v even heard RR technology might even one day bring back steam turbines due to increased efficiency. (of course, will be nothing like the steam engines of old, and frankly, I don't see it happening-point is, things change, what's old is new again, and there's more than one way to skin a cat) Generally, many posts have been right-either the train REALLY needs more than one for climbing grades, or, they need the HP/T for acceleration, OR the Class I RR's demand them for redundency. Frankly, I find it strange to see any LD train like the TE operating with just 1 engine. Sure, you can get a loaner engine from the class I partner, but, it won't be equipped with HEP....in my opinion, everything except coridor trains should have 2 passenger locomotives-things happen...but, the bean counters must have run the numbers and determined the cost to do so outweighs the risk of a failure.

 

[Swadian Hardcore]

True, the E units did have more than one prime mover, but, they were relatively short lived, and are gone-Just wasn't cost beneficial. To fix one, you still lose the entire engine. Might as well have two separate units. Of course, nothing in this world is new, heck, I'v even heard RR technology might even one day bring back steam turbines due to increased efficiency. (of course, will be nothing like the steam engines of old, and frankly, I don't see it happening-point is, things change, what's old is new again, and there's more than one way to skin a cat) Generally, many posts have been right-either the train REALLY needs more than one for climbing grades, or, they need the HP/T for acceleration, OR the Class I RR's demand them for redundency. Frankly, I find it strange to see any LD train like the TE operating with just 1 engine. Sure, you can get a loaner engine from the class I partner, but, it won't be equipped with HEP....in my opinion, everything except coridor trains should have 2 passenger locomotives-things happen...but, the bean counters must have run the numbers and determined the cost to do so outweighs the risk of a failure.

Hmm? Amtrak had E-units till 1980. I woudn't call over 40 years "short lived". Though I still like pax train with multiple locomotives just for high power. In my pinion acceleration is important.

 

[cirdan]

As to why idle for lengthy periods: Start up and shut down of a large diessel engine is not as simple as turning the key in your car. Fuel consumption at idle is very low, so unless the shutdown period will be very long it is better to leave it at idle.

Although modern engines are designed more with fuel efficiency and environmental emissions in mind and can actually start more easily and more cleanly, so actually making it economic to shut them down for shorter periods.

 

[cirdan]

It would be a bit more complex than that. Some new hybrid switchers do just that, but it hasn't worked out yet for road engines. Main reason is cost and maintenance-you would need two starters, two cooling systems, two oil systems, two main generators etc etc etc

Some of the diseil multiple unit trains in Britain have multiple diesel engines along the train. Rather than running all four at half power when that's what the train requires, two are shut down and two run at full throttle (for example) as they are more efficient at certain power output settings. The computer keeps track of which engines are up and which are down and for how long and cycles them to ensure equal operating hours and usage. It is one of the beauties of a diesel-electric that the prime mover doesn't have to be on the same vehicle as the traction motor, and so one diesel engine can power the electric traction motors along the full length of the train.

 

[jis]

Some of the diseil multiple unit trains in Britain have multiple diesel engines along the train. Rather than running all four at half power when that's what the train requires, two are shut down and two run at full throttle (for example) as they are more efficient at certain power output settings. The computer keeps track of which engines are up and which are down and for how long and cycles them to ensure equal operating hours and usage.

ALP45s also shut down one engine when its power is not required, like when cruising along at low to medium speed.

 

[George Harris]

Demanding two engines for redundancy in case one fails is much the same logically as demanding that your automobile have two engines. You simply do what it takes to avoid/minimize failures. It is far cheaper to maintain one engine well than it is to maintain two engines mediocrely

 

[Shortline]

1349721902[/url]' post='398313']Demanding two engines for redundancy in case one fails is much the same logically as demanding that your automobile have two engines. You simply do what it takes to avoid/minimize failures. It is far cheaper to maintain one engine well than it is to maintain two engines mediocrely

I agree for corridor service trains that often operate on multi-track main, and have rescue close at hand, but when a LD train locomotive fails, not only is the train dead in the water, unlike your car, it can't be pushed to the side of the road to let other traffic past-the whole line is shut down until it moves at worst, or trains must go around it on another track at best. The whole corridor plan is thrown off, which can have far reaching ramifications, sometimes for days on end to get sorted out. Not to mention, in the interim, there may be no lights, water, heat/air conditioning or toilets until another source of HEP is found. Not a great situation.....especially if in a remote location hundreds of miles from a relief loco. Failures are apparently rare, but I don't want to be on board when one happens!

 

[jis]

I agree for corridor service trains that often operate on multi-track main, and have rescue close at hand, but when a LD train locomotive fails, not only is the train dead in the water, unlike your car, it can't be pushed to the side of the road to let other traffic past-the whole line is shut down until it moves at worst, or trains must go around it on another track at best. The whole corridor plan is thrown off, which can have far reaching ramifications, sometimes for days on end to get sorted out. Not to mention, in the interim, there may be no lights, water, heat/air conditioning or toilets until another source of HEP is found. Not a great situation.....especially if in a remote location hundreds of miles from a relief loco. Failures are apparently rare, but I don't want to be on board when one happens!

Specially in the middle of winter in the middle of Montana in a blizzard it could devolve into a life or death situation. There is very good reason to have two locomotives on the LD trains.

 

[PRR 60]

I agree for corridor service trains that often operate on multi-track main, and have rescue close at hand, but when a LD train locomotive fails, not only is the train dead in the water, unlike your car, it can't be pushed to the side of the road to let other traffic past-the whole line is shut down until it moves at worst, or trains must go around it on another track at best. The whole corridor plan is thrown off, which can have far reaching ramifications, sometimes for days on end to get sorted out. Not to mention, in the interim, there may be no lights, water, heat/air conditioning or toilets until another source of HEP is found. Not a great situation.....especially if in a remote location hundreds of miles from a relief loco. Failures are apparently rare, but I don't want to be on board when one happens!

Specially in the middle of winter in the middle of Montana in a blizzard it could devolve into a life or death situation. There is very good reason to have two locomotives on the LD trains.

In fact, for the Empire Builder in the winter, BNSF has required three locomotives. Not sure if that will be the case again this year.