Push Pull Freight

[RichmondCommu]

G'day,

Given the number of top 'n' tail infrastructure trains that run in this country would it not make more sense to build some freight DVT's? Whilst I appreciate that not all trains are of the same length surely at places like Wellingborough Finedon Road a siding could be provided with a few DVT's parked up?

Your thoughts and comments would be most welcome!

Rcihmond Commuter!

 

[455driver]

There are not any push/pull freights though.

The loco on the back is hauled dead in rear and is started up (and used) when the train reverses and so becomes the hauling loco, the one which was previously at the front (before the reversal) is then shut down and hauled dead in rear.

It saves the loco having to run round the train or even having to find somewhere where it is possible to perform the run round.

it is actually just easier from an operational viewpoint to have the second loco on the back of the train.

 

[RichmondCommu]

There are not any push/pull freights though.

The loco on the back is hauled dead in rear and is started up (and used) when the train reverses and so becomes the hauling loco, the one which was previously at the front (before the reversal) is then shut down and hauled dead in rear.

It saves the loco having to run round the train or even having to find somewhere where it is possible to perform the run round.

it is actually just easier from an operational viewpoint to have the second loco on the back of the train.

Thanks for your reply but this is my point. Would it not be more efficient to use a DVT as this would then allow the other loco to be employed else where earning revenue for its FOC?

 

[455driver]

The 2 locos are completely separate (apart from the brake pipe obviously) so you would need to wire every single freight wagon to get the electrical signals from the DVT to the loco with all the resultant problems from that.

It is a big enough problem on fixed formation with signal degradation just imagine all the problems on freight trains which can change formation every day.

 

[asylumxl]

I think the main issue with this idea is how the signal would be transfered between the loco and the DVT. Using the traditional method of cables would just be far too inconvenient and I am unsure if any wireless solution would be safe or reliable enough.

Edit: 455driver got there quicker! Git... :P

 

[HSTEd]

The 2 locos are completely separate (apart from the brake pipe obviously) so you would need to wire every single freight wagon to get the electrical signals from the DVT to the loco with all the resultant problems from that.

It is a big enough problem on fixed formation with signal degradation just imagine all the problems on freight trains which can change formation every day.

In the US they now have Electronically controlled pneumatic braking systems that pass two wires and one brake pipe down the train in leiu of the ordinary braking settup (Frankly they are the future of freight operations, the operational benefits are many and manifold) which can also be used as locomotive control lines thanks to the data circuit having rather more bandwidth than required for braking.

They also have remote loco control systems using radio (see Locotrol).

 

[455driver]

We are not in America though and none of that stuff is cleared for use over here, it would cost a fortune to get it cleared for use and then fit it to all the locos and wagons just to save a few locos top and tailing.

America is huge with huge freight trains covering huge distances so the economy of scale is there, a 20 wagon ballast train going an hour down the line to sit in a worksite for 5 hours and then run the hour back to base isnt quite in the same league.

 

[RichmondCommu]

I think the main issue with this idea is how the signal would be transfered between the loco and the DVT. Using the traditional method of cables would just be far too inconvenient and I am unsure if any wireless solution would be safe or reliable enough.

Edit: 455driver got there quicker! Git... :P

Now you and 455 make some very valid points here however you could make a start with rail head treatment trains which seem to run in fixed formations. And then perhaps start to try and identify any other fixed rakes that could be adapted?
--- old post above --- --- new post below ---

We are not in America though, Brazil has some really hot Women but oops thats enough of that!

Hang on my wife is reading this! My better half assumes that this forum is innocent railways chat!

 

[455driver]

I have edited that bit off only 10 seconds after posting it.

 

[RichmondCommu]

I have edited that bit off only 10 seconds after posting it.

No need to have done that! Nothing wrong with a bit of light hearted humour
--- old post above --- --- new post below ---

America is huge with huge freight trains covering huge distances so the economy of scale is there, a 20 wagon ballast train going an hour down the line to sit in a worksite for 5 hours and then run the hour back to base isnt quite in the same league.

I appreciate this but even so a loco might easilly be more than an hour from its home depot given how few depots there are now a days. As an example if two DBS loco's are operating RHT trains on the S & C how far is their nearest depot? Not only that but surely it would allow more DBS loco's be left on the continent?

 

[asylumxl]

They also have remote loco control systems using radio (see Locotrol).

I believe this is only for low speed operation and similar things were trialled in the UK. This would not be suitable for a mainline freight operation unfortunately. Willing to be corrected ofcourse.
--- old post above --- --- new post below ---

I appreciate this but even so a loco might easilly be more than an hour from its home depot given how few depots there are now a days. As an example if two DBS loco's are operating RHT trains on the S & C how far is their nearest depot? Not only that but surely it would allow more DBS loco's be left on the continent?

RHTT (in the South at least) is known to be operated by the Network Rail MPVs. This is more efficient in my opinion.


DR 98975 & 98925 MPV works the 3S75 RHTT at Shoreham Station on 26-11-11. Copyright Ian Cuthbertson by I C railway photo's, on Flickr

 

[HSTEd]

I believe this is only for low speed operation and similar things were trialled in the UK. This would not be suitable for a mainline freight operation unfortunately. Willing to be corrected ofcourse.

Although one of the early uses was indeed in yard shunting operations for obvious reasons (precision computer control of a shunter on a hump has major benefits) it has now been adapted for freight mainline use, including to control various locomotives on the Sishen-Saldanha line, replacing the previous technique of having numerous crews in the various parts of the formation communicating using CB radios.

And for reference, here is a typical train.

Additionally formations worked like that by MPVs are probably through wired already, and with modern electronics the signals can all be transmitted over a single pair of wires so the jumpers are hardly likely to bankrupt anyone.

 

[asylumxl]

What kind of speed are we talking for the train you referred to?

 

[HSTEd]

What kind of speed are we talking for the train you referred to?

Supposedly speeds on descending sections can reach 50mph, although I believe when you are using conventional US style air brake equipment you have to be very careful not to deplete your air supply so ordinary practice would be to run down slower than that.

 

[ModernRailways]

Now you and 455 make some very valid points here however you could make a start with rail head treatment trains which seem to run in fixed formations. And then perhaps start to try and identify any other fixed rakes that could be adapted?

The RHTT's have ran with DVT's. They used the old EWS managers one along with a 67 last year. I also recall seeing a one with a 66. I've found this image on Flickr: clicky here if not displaying below

 

[jopsuk]

Whilst it isn't "push pull", tramsitting locomotive control signals by wireless means is a technology that is proven in the US and Australia- that's how they run their mega freights with locomotives through the train. In the US at least this can involve twisting mountain routes and tunnels.

 

[#1 driver]

the only top'n'tail trains I drive are the HOBC and re-sleeper trains .
they come over from Carlisle and they need both locos to be driven to get up the hills .
when they get into site , they are split and work as 2 trains .

so the option of a DVT here is not a valid one .

 

[edwin_m]

Most freight trains are heavier than passenger trains and it is possible that there would be a derailment risk with the loco propelling them, except at very low speeds as happens now for shunting etc.

 

[Cliveblackpool]

There was push pull working on the Bodmin Road to Bodmin General section/ Boscarne Junction, (reversal & a limited turnround at Gerneral) for freight to Wenford Bridge, until it closed around 1978.
Shunter was on the rear, and Guards Van on the front.
Although the wagons were empty, the engine ran very hot as air to the radiator was shielded by the wagons.

 

[hairyhandedfool]

Now you and 455 make some very valid points here however you could make a start with rail head treatment trains which seem to run in fixed formations. And then perhaps start to try and identify any other fixed rakes that could be adapted?....

....RHTT (in the South at least) is known to be operated by the Network Rail MPVs. This is more efficient in my opinion....

MPVs are 'master and slave', or, put another way, push-pull. I believe an MPV was used on a freight trial for the feasibility of using them for fixed formation freight trains. It was a log train and the MPVs couldn't carry any freight due to weight concerns (when empty). A specially formed 'power-twin' set was used, so I'm not sure if it was push-pull, but if one had the power to pull the lot, then push-pull should be possible.

http://i423.photobucket.com/albums/pp313/TheBufoon/Windhoff MPV/75701115512080.jpg
(picture found through Google)

In Germany, Windhoff have produced sets for container traffic.

 

[HSTEd]

MPVs are 'master and slave', or, put another way, push-pull. I believe an MPV was used on a freight trial for the feasibility of using them for fixed formation freight trains. It was a log train and the MPVs couldn't carry any freight due to weight concerns (when empty). A specially formed 'power-twin' set was used, so I'm not sure if it was push-pull, but if one had the power to pull the lot, then push-pull should be possible.
.

I read the report, I believe they concluded that it would be feasible to load logs on the MPV and studied the capacity that would be achievable, but decided that the cost of fabricating the necessary framework to hold said logs was prohibitive for a simple test run. Instead I believe they left the normal equipment fit on the driving vehicles as ballast to improve the tractive effort that could be generated to handle a fully loaded train.

Which is why they only used the wagons they had lying around.
And I think the term "push-pull" is being used to refer generally to double ended operation (using all motive power) generally instead of the specific case where one locomotive and one driving trailer are marshalled at opposite ends of a formation.

 

[jopsuk]

"Multiple unit" type freight really hasn't got very far- I think the evaluation Windhoff set that went to Austrlia for container trialls didn't last long, and the Japanese (who've all but eliminated locos from passenger operations, even the Imperial train is an EMU) have a couple (but no more) of container EMUs.

But then, as I mentioned above, mega freights in Australia, the US, Canda are only viable with locomotives in the middle and on the rear of the train, else drawbar forces get too high- and they use radio systems to remotely control from the front

 

[bronzeonion]

I think its a good idea but only would be practical if the trains to go push pull were in a fixed formation so could have a cab at the end of the last wagon of the formation. Could also be made more flexible by having a wagon with a cab at either end of the formation.

 

[hairyhandedfool]

....And I think the term "push-pull" is being used to refer generally to double ended operation (using all motive power) generally instead of the specific case where one locomotive and one driving trailer are marshalled at opposite ends of a formation.

I would tend to say a loco at both ends is more top and tail than push-pull, though I guess the HST is the only example, in the UK, of a loco working at both ends simultaneously atm.

 

[Mugby]

Top and tailing has always seemed a rather extravagent way of working to me
(except where there's no run round facility of course)

Is it all so they don't have to employ shunters anymore?

 

[GB]

Top and tailing has always seemed a rather extravagent way of working to me
(except where there's no run round facility of course)

Is it all so they don't have to employ shunters anymore?

Not at all. Speaking from an engineering work stand point its purely done from an operational sense where either no run round facility exists, pathing is too tight for a run round or because engineering work sites require it, as the train may split and worked as two separate trains . Top and Tail is more expensive than utilising a shunter who is already on the pay role.

Also, when it comes to engineering work, locos usually cascade onto other trains on site (if they are coming back out the way they came in) so the first train in will be single engined in and top and tailed out and the last train in will be top and tailed in and singled engined out.

 

[DarloRich]

Top and tailing has always seemed a rather extravagent way of working to me
(except where there's no run round facility of course)

Is it all so they don't have to employ shunters anymore?

For engineering works it is just easier to have a loco on each end. It saves faffing about at a work site and allows the train to be positioned within a work site without the need to run round. It allow allows you to get the train away as quickly as possible.

 

[RichmondCommu]

RHTT (in the South at least) is known to be operated by the Network Rail MPVs. This is more efficient in my opinion.

I concur that MPV's are more efficient but that hasn't stopped top 'n' tail operations on RHTT. Hence the filthy state of some Class 66's once the season is over.

 

[Bald Rick]

I concur that MPV's are more efficient but that hasn't stopped top 'n' tail operations on RHTT. Hence the filthy state of some Class 66's once the season is over.

You might think they are more efficient, but they are considerably less reliable and thus less effective. In terms of cost per output (clean rails) they are much less efficient. Hence more loco based RHTTs are on the way.

 

[455driver]

You might think they are more efficient, but they are considerably less reliable and thus less effective. In terms of cost per output (clean rails) they are much less efficient. Hence more loco based RHTTs are on the way.

Good, I hate following those MPvs when they are on RHTT work, my train slips and slides all over the place, and yes I do hand notch etc before all the "old end" start going on about me not being able to drive properly.