Electric Freight

[YorkshireBear]

Basically im wondering what the advantages and disadvantages are of electric freight. I'm studying civil engineering and expanding electrification is one of my job interests.

It doesn't seem to happen much and was wondering why? or whether its just lack of investment rather than it not being good.

I was also wondering as a tag along to this. How feasable would it be to electrify to say knottingley so electric stock can take intermodal and other traffic up the ECML then swap for diesel to take it to the various depots and yards in west yorks.

 

[Flying Snail]

The simple answer is that the majority of freight runs have at least a part of their trip away from the wires.

Added to the fact that swapping locos, running round and any shunting moves that can be avoided have been vigorously removed by the British rail industry and you have a huge amount of diesel freight haulage under wires.

Filling in gaps in the electrified network will help but there is also the issue of unelectrified freight loading points, in some cases OHLE is not possible and the use of diesel shunting in the freight compounds will still be necessary. Part of any push to switch as much freight over to electric as possible would have to be disincentives for operators to use diesels for long distances under wires, perhaps a heavy surcharge on track access fees if continuous journeys over a certain length are made with diesels on electrified lines.

 

[Yew]

Maybe diesel electric locomotives could be used like with pantographs and stuff?

 

[stanley T]

Bring back the electrodiesel - an electric with a small (500hp or so) diesel engine just for shunting and unelectrified sidings.

The Bombardier Traxx Last Mile loco

 

[Yank 119]

Maybe diesel electric locomotives could be used like with pantographs and stuff?

Bring back the electrodiesel - an electric with a small (500hp or so) diesel engine just for shunting and unelectrified sidings.

How about actual dual mode locomotives?

http://en.wikipedia.org/wiki/ALP-45DP

 

[Royston Vasey]

How about actual dual mode locomotives?

http://en.wikipedia.org/wiki/ALP-45DP

Much more useful than a last mile diesel, since the amount of electrification we'd need to make even that work is staggering. A dual mode loco is an interesting concept, since with a heavy haul freight, the relative inefficiency of transporting two drivetrains becomes much less significant when you're talking a train of thousands of tonnes, compared to two powertrains in a lightweight EDMU, e.g. bimode IEP or the proposed electro-Voyager. The problem would be fitting what is essentially two separate ~5000hp drivetrains in one loco in the UK loading gauge. You may as well put a 92 and a 66 double heading on every train, using electric if available and diesel if not!

The well to wheel sums would be interesting for dual mode. Is the modest WtW energy efficiency saving on AC c.f. a modern diesel actually worth the additional weight on board, not to mention expenditure of energy and finance on new infrastructure (OHLE) and equipment (traction)? I think it's probably unlikely to pay back in either energy or monetary terms.

 

[T163R]

Bring back the electrodiesel - an electric with a small (500hp or so) diesel engine just for shunting and unelectrified sidings.

Well the Traxx Last Mile Diesel is supposed to arrive in UK at some point...

 

[HSTEd]

As someone earlier in the thread has said, freight locomotives are far more orientated towards tractive effort than having huge power to weight ratios like passenger rolling stock, so the carriage of a genset doesn't have that big a negative impact.

A true electrodiesel is far superior to the TRAXX "Last Mile" locomotive as it could be used as a normal diesel locomotive as the situation requires, gaining the same operational benefits apparently derived from the deployment of EDMUs by SNCF.
The Class 70 shows that there is plenty of space inside locomotive bodies at this point (walkways down both sides? really?) and it shouldn't be too hard to fit transformer gear, pan gear and probably a set of third rail pickup shoes, as an AC traction motor control system would be able to use that really quite easily with only the extra cost of the shoebeams and another few thousand linse in the control software.

They could just deny track access to any purely diesel mainline locomotives ordered after a cutoff date to prevent additional orders?

 

[MacCookie]

As someone earlier in the thread has said, freight locomotives are far more orientated towards tractive effort than having huge power to weight ratios like passenger rolling stock, so the carriage of a genset doesn't have that big a negative impact.

A true electrodiesel is far superior to the TRAXX "Last Mile" locomotive as it could be used as a normal diesel locomotive as the situation requires, gaining the same operational benefits apparently derived from the deployment of EDMUs by SNCF.
The Class 70 shows that there is plenty of space inside locomotive bodies at this point (walkways down both sides? really?) and it shouldn't be too hard to fit transformer gear, pan gear and probably a set of third rail pickup shoes, as an AC traction motor control system would be able to use that really quite easily with only the extra cost of the shoebeams and another few thousand linse in the control software.

And how much will all that extra gear weigh?

Ewan

 

[Yew]

Pretty negligible compared to the weight of the freight it pulls

 

[HSTEd]

However much a pan and its supporting auxiliaries (the raising and lowering equipment and that) and a 25kV - ~650V transformer weighs, the traction control electronics would take care of the rest.
A few tonnes at most, its really negligble compared to the weight of the locomotive, let alone the train, and remember many freight locomotives are deliberately heavily built to increase the tractive effort they have available.


EDIT: You also have to rememebr that the locomotive would probably carry less fuel under normal circumstances, this is a significant weight when operating over hundreds of miles every day, many of which are wired.

 

[apk55]

Electric locomotives can be made with very high power to weight such that even at speed the power output is limited by adhesion up to over 60mph. While this is desirable for passenger trains on a demanding schedule, for freight with a top speed of less than 80 mph this appears pointless and I would suspect many locomotives rarely work at full output for any length of time. Therefore ballasting an electric locomotive with a diesel engine to increase the weight and tractive effort would not be a problem.

In many parts of this country (and in many parts of Europe) I can see most major lines being electrified with the none electrified lines being freight only or only with a slow regional or local passenger trains. Therefore a electro diesel locomotive need not have a particularly powerful diesel engine for working these lines as compared to working on an electric line where a higher performance would be desirable.

Diesel engines lose efficiency when working on part load (and use fuel when idling) so I like the idea of a twin or multi engined locomotive, where engines can be shut down on light duties and shunting. This may become more important as oil price rises.

I agree with HSTEd that an electric class 70 would be a good idea. Replace a big diesel with twin diesel gen-sets and a transformer rectifier and you would have a good universal heavy freight loco. I would think that 5MW on AC and 1.5MW on diesel would be easily possible. In addition Third rail capability could be added for minimal extra cost.

 

[Royston Vasey]

However much a pan and its supporting auxiliaries (the raising and lowering equipment and that) and a 25kV - ~650V transformer weighs, the traction control electronics would take care of the rest.
A few tonnes at most, its really negligble compared to the weight of the locomotive, let alone the train, and remember many freight locomotives are deliberately heavily built to increase the tractive effort they have available.


EDIT: You also have to rememebr that the locomotive would probably carry less fuel under normal circumstances, this is a significant weight when operating over hundreds of miles every day, many of which are wired.

That's a very good point. On paper, a loco diagrammed to do, say, Felixstowe to Tyne Yard and return via ECML (random fictitious example) only needs to use/carry ~150 miles of diesel rather than 600. Whether this would actually work in practice is maybe a little less straightforward, due to the loss of operational flexibility. That loco couldn't instantly be switched to another diagram, or be diverted via the S&C for example.

Again though, the % saving in efficiency from the fuel weight (3-4 tonnes perhaps?) is probably not significant due to the overall weight of the consist, and may not be worth the sacrifice in terms of flexibility.

 

[eMeS]

On the WCML through Milton Keynes, I fairly frequently see double headed electric hauled freight trains, but can't recall seeing any double headed diesel hauled. (Sorry, I didn't note what class of locos were involved.)

 

[GB]

The only double headed electric freight services are those used by Freightliner and their class 86. A single 86 is under powered compared to say a 66 or a 90 which is why they need 2 for most occassions.

 

[MacCookie]

However much a pan and its supporting auxiliaries (the raising and lowering equipment and that) and a 25kV - ~650V transformer weighs, the traction control electronics would take care of the rest.
A few tonnes at most, its really negligble compared to the weight of the locomotive, let alone the train, and remember many freight locomotives are deliberately heavily built to increase the tractive effort they have available.


EDIT: You also have to rememebr that the locomotive would probably carry less fuel under normal circumstances, this is a significant weight when operating over hundreds of miles every day, many of which are wired.

Weight of the train isn't the problem. Axle weight of the locomotive is. A Class 66 weighs in at 126 tonnes and is at the maximum axle weight for RA7 (which gives access to most of the network).

If, as you suggest, the extra gear only weighs a few tonnes, then a bi-mode equivalent of a 66 would no doubt come in at under 136 tonnes (RA8).

I'm not sure that reducing the capacity of the fuel tank would be much use - you'd severely limit the range (DRS can get about 600 miles out of a 66 on a container train with a 5,500l fuel tank). While a short range (say, 100 miles), would be fine for occasional use, if you want the flexibility to run the train via diesel only diversionary routes, you'd need at least 300 miles. So if you cut the fuel capacity in half, you'd probably save about 2.2tonnes (diesel has a SG of 0.82, so 5,500l weighs about 4.5 tonnes).

Ewan

 

[YorkshireBear]

Sounds better plan to me as it does save a considerable amount of hassle in changing locos. But i would keep the fuel tank full in my opinion. LIke said if the ECML closes it can divert. I think the weight save is negligible.

 

[HSTEd]

I believe the Class 66 being at the maximum allowable axle loading for RA7 is the case of the designers ballasting down the locomotive to the maximum allowable degree, if you look at the '66s power to weight ratio it is far lower than most passenger diesels, so you could probably remove some of the unneccesary weight to make up for teh electrical equipment.

I wasnt referring to shrinking the fuel tank, I was referring to not filling it fully under normal operations, but as you say its probably a negligible difference.

 

[Hydro]

The only double headed electric freight services are those used by Freightliner and their class 86. A single 86 is under powered compared to say a 66 or a 90 which is why they need 2 for most occassions.

A single 86 is more powerful than a 66. The lowest powered 86's put out the equivalent of 3,600hp, running to 4,040hp and up to 5,000hp for the class 87 testbeds. I believe FL run double headed locos for better adhesion characteristics, i.e. two locos share the load between them and they keep their feet better. The 86/6's had no regearing, and were limited on paper to 75mph with the ETH isolated. 86501 is a lower geared example and is normally seen on it's own.

Electric freight is advantageous. It's easier to timetable due to superior acceleration - electric locos are more powerful, on the whole, than their diesel equivelents.

 

[MacCookie]

I believe the Class 66 being at the maximum allowable axle loading for RA7 is the case of the designers ballasting down the locomotive to the maximum allowable degree, if you look at the '66s power to weight ratio it is far lower than most passenger diesels, so you could probably remove some of the unneccesary weight to make up for teh electrical equipment.

I wasnt referring to shrinking the fuel tank, I was referring to not filling it fully under normal operations, but as you say its probably a negligible difference.

Yes, the 66 is at the maximum allowable weight for RA7. And all the gear inside is necessary. That's why when the low emissions variant was produced, the additional weight of the kit meant that something else had to be cut. The thing that was cut was the fuel tank capacity.

As for not filling it, the total weight of the loco is based on the fuel tank being full.

Ewan

 

[HSTEd]

The Class 66 has a power to weight ratio of approximately 25.5hp/t.
A Class 43 power car has a power to weight ratio of approximately 32.1hp/t.

Excluding the differences in the transmission efficiencies of the traction generator/motor settup which can likely be put down to 30 years of advancements in electrical engineering it woudl appear that diesel electric locomotives with substantially higher power to weight ratios than the Class 66 are feasible, this would seem to indicate that an ED locomotive with the same RA as the Class 66 adn similar power output could be built.

The reason that the Class 66 Low Emissions vehicle had to have the fuel tank shrunk to lighten the weight is that the additional weight, following what appears to be dominant american practice, is in the frame of the locomotive, this is partially a result of insane American crash standards.
Removing this additional weight would likely require a complete redesign of teh locomotives structure which would probably be a competely new design probably at great expense.

EDIT: It would appear that the Powerhaul that is several tonnes heavier than a Class 66 has the same RA7 availability, which would seem to indicate that adding a handful of tonnes to it would not be disastrous.

 

[MacCookie]

The Class 66 has a power to weight ratio of approximately 25.5hp/t.
A Class 43 power car has a power to weight ratio of approximately 32.1hp/t.

Excluding the differences in the transmission efficiencies of the traction generator/motor settup which can likely be put down to 30 years of advancements in electrical engineering it woudl appear that diesel electric locomotives with substantially higher power to weight ratios than the Class 66 are feasible, this would seem to indicate that an ED locomotive with the same RA as the Class 66 adn similar power output could be built.

Are you a MechEng?

The reason that the Class 66 Low Emissions vehicle had to have the fuel tank shrunk to lighten the weight is that the additional weight, following what appears to be dominant american practice, is in the frame of the locomotive, this is partially a result of insane American crash standards.
Removing this additional weight would likely require a complete redesign of teh locomotives structure which would probably be a competely new design probably at great expense.

I thought that you said the extra weight was ballast?

Interesting that they'd build a locomotive designed for export to US design standards.

It's also worth noting that EU standards have changed, hence the rather interesting front ends on more recent designs (eg, Class 70 and Class 380).

EDIT: It would appear that the Powerhaul that is several tonnes heavier than a Class 66 has the same RA7 availability, which would seem to indicate that adding a handful of tonnes to it would not be disastrous.

I had a ponder over that, as the Class 60 is 130 tonnes and RA7. However, it would appear that Route Availability isn't just axle load. A number of factors, including axle spacing, also have an impact.

Ewan

 

[HSTEd]

Are you a MechEng?

Actually no, my (two thirds completed) degree is in Chemistry, but I have had an interest in Mechanical Engineering subjects for years.

I thought that you said the extra weight was ballast?

Interesting that they'd build a locomotive designed for export to US design standards.

It is ballast in that it is not required to allow the locomotive to operate here, it is however built into the frame because thats how American designers have always increased the weight of locomotives to increase tractive effort.

It's also worth noting that EU standards have changed, hence the rather interesting front ends on more recent designs (eg, Class 70 and Class 380).


I had a ponder over that, as the Class 60 is 130 tonnes and RA7. However, it would appear that Route Availability isn't just axle load. A number of factors, including axle spacing, also have an impact.

Ewan

Ive also been pondering, it would appear that the Class 67 has the same engine, alternator and control equipment as the Class 66 with only four traction motors on a Bo-Bo chassis for under a hundred tonnes.
It does not seem beyond possibility that two additional axles, traction motors and the transformer equipment could fit on in under 30 tonnes, even accounting for the structural modifications to allow the extra axles to reduce overall axle weight to RA7.

RA is a rather complex measurement and I unfortunately dont have access to the standard that undoubtably exists somewhere that allows for it to be quantified.

 

[jopsuk]

Electrifying the Midland and Great Western Mainlines, and the major branches of the East and West Coast as well as the port branches of the Great Eastern (and other) mainlines, plus the Cross Country and Transpenine network, and you'd have a much more viable electric freight network- and yes, for the pedants, you'd need to Ely-Ipswich as well.

Diesel shunters in the container yards (and other freight depots where top access is required) surely shouldn't be that big an issue? Even better if a strong automatic coupling standard could be created to allow the shunters to be swiftly attached and detached at the yard entrances.

 

[GB]

and yes, for the pedants, you'd need to Ely-Ipswich as well.

...and Ely North Jnc - P'borough!

New build freight terminals could be designed and built with electrification in mind however I think you would struggle to get it to work efficiently with most existing terminals.

 

[jopsuk]

...and Ely North Jnc - P'borough!

You missed the bit where I said "Cross Country network". The Birmigham-Stansted service uses that line.

I'm not convinced a high-throughput Container terminal could be built to work with wires

 

[HSTEd]

You missed the bit where I said "Cross Country network". The Birmigham-Stansted service uses that line.

I'm not convinced a high-throughput Container terminal could be built to work with wires

If we are using Class 92s or a successor there is no need for wires, the loading line would just have third rail

 

[GB]

You missed the bit where I said "Cross Country network". The Birmigham-Stansted service uses that line.

I'm not convinced a high-throughput Container terminal could be built to work with wires

Indeed I did!

It is entirely possible to use OLE in new build container terminals, the OLE would just need to be stopped before you get to the working area and safe guards would need to be put in place to stop cranes coming into XX feet of it. You would obviously need a diesel pilot to haul the train into the terminal and to do the shunting aspect.

 

[Hydro]

If we are using Class 92s or a successor there is no need for wires, the loading line would just have third rail

The former Southern Region judged third rail electrification in goods yards to be sufficiently risky in shunting operations to warrant installation of 750v DC overhead tramline style electrification for use with early DC electrics. Subsequent SR electric locos were electro-diesel (73 and 74). This was also the reason why buckeye couplers and high level brake pipes and control jumpers were installed, to avoid shunters having to go between around live conductor rails. Areas where coupling and uncoupling took place of stock not fitted with these, had guard boarding installed, but was still risky. Good luck trying to have third rail in a modern intermodal yard.

Best bet is for diesel shunters to take the trains in off a reception line.

It's worth remembering that Cl.92's are fairly limited on 750v in where they can go due to massive current draw. Even on the currently cleared routes there are SA restrictions on number of locos powering in a section. Any expansion of Cl.92 operations may need expensive supply upgrade work.

 

[GB]

Even with kick boards 3rd rail would be of no use...way to risky for the types of activity that goes on in those sorts of yards.