Freight over 3rd rail

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pompeyfan

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After reading the post regarding class 69s potentially releasing some class 73s in the Kent area, it had me wondering what is the longest freight journey over 3rd rail? I’m aware there may be some last mile diesel involved in yards etc but surely more freight could be 73 hauled without switching locos mid journey? My guess would be the Southampton Gypsum train?
 
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zwk500

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After reading the post regarding class 69s potentially releasing some class 73s in the Kent area, it had me wondering what is the longest freight journey over 3rd rail? I’m aware there may be some last mile diesel involved in yards etc but surely more freight could be 73 hauled without switching locos mid journey? My guess would be the Southampton Gypsum train?
To my knowledge all freight in the 3rd rail area is currently hauled by diesel. 73s run the seasonal departmental trains (and some stock moves). I may well be corrected by later posters.
 

Deepgreen

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I think the requirement for double-heading (at least) with 73s on today's freight weights may be a limiting factor. Even with a combined 3,200hp on electric, they are Bo-Bos so don't have the tractive effort of Co-Co locos designed for freight. Then there is the issue of the sections which may need diesel - taking it down to 1,200hp.
 

Fincra5

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GBRf have run 92s over the Juice, not too long ago! HS1 has obvs taken most 92's off Kent's Juice...

There are deffo routes where something like a Bi-Mode would be useful! Newhaven to Purley for example... But then Power Supply can become a limiting factor.
 

43096

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I think the requirement for double-heading (at least) with 73s on today's freight weights may be a limiting factor. Even with a combined 3,200hp on electric, they are Bo-Bos so don't have the tractive effort of Co-Co locos designed for freight. Then there is the issue of the sections which may need diesel - taking it down to 1,200hp.
Unless they use a 73/9, which have similar outputs on electric and diesel.
 

zwk500

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GBRf have run 92s over the Juice, not too long ago! HS1 has obvs taken most 92's off Kent's Juice...

There are deffo routes where something like a Bi-Mode would be useful! Newhaven to Purley for example... But then Power Supply can become a limiting factor.
Unless they use a 73/9, which have similar outputs on electric and diesel.
Surely a even a 73/9 (or a pair) would struggle to get a loaded aggregate train from Mitre Bridge to Acton Yard on it's diesel power alone?
 

43096

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Surely a even a 73/9 (or a pair) would struggle to get a loaded aggregate train from Mitre Bridge to Acton Yard on it's diesel power alone?
What hauls them currently? A 66?
 

hwl

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After reading the post regarding class 69s potentially releasing some class 73s in the Kent area, it had me wondering what is the longest freight journey over 3rd rail? I’m aware there may be some last mile diesel involved in yards etc but surely more freight could be 73 hauled without switching locos mid journey? My guess would be the Southampton Gypsum train?
Much more likely to be releasing 66s on heavier engineering trains or infrastructure supply (bulk ballast) trains in/out of Tonbridge Yard to allow them to do potential HS2 work instead...
Not much change likely in 73s use.
 

43096

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Yes. What rating are 73/9s on diesel, I thought they're c.1,500hp but quite light on their axles?
Correct on the rating, so a pair would have a similar output to a 66, but over 8 axles rather than 6. Given the modern control systems on the 73/9s (do they have SEPEX - can’t remember) I would think a pair could handle it.
 

pompeyfan

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Is there many/any freight flows that could be 3rd rail powered with a last mile system?
 

Deepgreen

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Correct on the rating, so a pair would have a similar output to a 66, but over 8 axles rather than 6. Given the modern control systems on the 73/9s (do they have SEPEX - can’t remember) I would think a pair could handle it.
You may be right, but a 66 has a TE of 92,000lb whereas a pair of 73s has around 75,000lb. They could give it a go but might struggle. The extra two axles may help. I think, though, that the 73s are just regarded as lighter train-weight units. There is a minimal strategic push to have freight electrically-hauled anyway.
 

popeter45

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isnt one of the big issue the fact that most third rail areas not have the power capacity for frieght?
even a 12 car EMU must draw draw far less power than a electric loco struggling with a aggregate load would?
 
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After reading the post regarding class 69s potentially releasing some class 73s in the Kent area, it had me wondering what is the longest freight journey over 3rd rail? I’m aware there may be some last mile diesel involved in yards etc but surely more freight could be 73 hauled without switching locos mid journey? My guess would be the Southampton Gypsum train?
I think you're right. 139 miles over the juice with a Cl.66. Just the first bit in the sidings at Mountfield and the last 1/2 mile into Soton W Docks from Millbrook lack the 3rd rail.
 

swt_passenger

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The fairly limited number of 73s I have seen on freight or infrastructure duties in the Hampshire area have almost all been operating on diesel. I suspect in places further east where they’re a bit more common they’re being chosen for their RA number compared to a 66, rather than the benefits of electric power...
 

Domeyhead

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There's a good piece by Ian Walmsley in the current Modern Railways. Not about Class 73s or third rail but the issue of electric freight haulage, timings and multiple modes. The upcoming class 93 is already tri mode - if it became a quad mode it would gobble up all southern freight at a canter.
 

HSTEd

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even a 12 car EMU must draw draw far less power than a electric loco struggling with a aggregate load would?

Not really.
If performance comparable to diesel is acceptable, a Class 66 has only 2240kW at rail.
That makes it somewhere between eight and nine cars of Class 377 formation.
 

Grumbler

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isnt one of the big issue the fact that most third rail areas not have the power capacity for frieght?
even a 12 car EMU must draw draw far less power than a electric loco struggling with a aggregate load would?
This is probably a bonkers idea, but would it be feasible to boost the power at selected places by installing a second third rail on the other side? Or would this fry the running rails?
 

DustyBin

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This is probably a bonkers idea, but would it be feasible to boost the power at selected places by installing a second third rail on the other side? Or would this fry the running rails?

It’s the substations etc. that are the problem, not the 3rd rail itself.
 

Carlisle

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Not a lot of spare capacity in the GBRf 73/9 fleet beyond their contracted infrastructure work.
It’s a shame the industry has only opted to refurbish 50-60 year old traction rather than meet the challenge of introducing a new fleet of 3rd rail capable locos
 

pompeyfan

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Is there actually that many flows though? The gypsum was identified as the longest, followed by the Acton - Newhaven aggregates but I can’t think of much else.
 

D365

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It’s a shame the industry has only opted to refurbish 50-60 year old traction rather than meet the challenge of introducing a new fleet of 3rd rail capable locos
What challenge is that? What would be the point when 750V is clearly inadequate for anything other than metro operations.
 

CW2

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What challenge is that? What would be the point when 750V is clearly inadequate for anything other than metro operations.
750V DC was entirely adequate for freights to / from the Channel Tunnel, hauled by class 92s.
 

southern442

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What challenge is that? What would be the point when 750V is clearly inadequate for anything other than metro operations.
I wouldn't necessarily call a lot of routes in 3rd rail land metro operations (although plenty in London are)
 
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