Will the class 68 loco oprerate on the GOBLIN line

[DownSouth]

Just as a quick 6-axle DC drive versus 4-axle AC drive performance comparison, currently the biggest US diesel loco supplier, GE, is offering a version of their normal 6-axle AC drive freight loco with only 4 axles powered (A1A-A1A axle configuration) - see http://en.wikipedia.org/wiki/GE_Evolution_Series#ES44C4

The idea is that these cost (and perform) about the same as their DC-drive, 6 powered axle equivalents. The jury is probably still out on the relative real-world performance, but one of the big US railroads is amassing a sizeable fleet of them, so they are presumably convinced.

And in Australia, freight operators have been exploiting the same conversion factor but in the opposite direction - the loading gauge has never allowed the big 4500kW prime movers like the GEVO here, but they can replace a string of four 2400kW DC traction diesel locos with just two 3300kW AC traction locos to haul the same trains with a slight increase in performance. The fact that AC traction motors don't have brushes which need replacing after every round trip across the Trans-Australia Railway is just as great an advantage as the performance.

The Class 68 will be a fine mixed traffic loco. It won't do the heaviest freight or the fastest mainline express trains, but no other British mixed traffic loco in the past has done that either.

 

[ac6000cw]

The Class 68 will be a fine mixed traffic loco. It won't do the heaviest freight or the fastest mainline express trains, but no other British mixed traffic loco in the past has done that either.

I agree

 

[electrolux]

KiloNewton. A measurement of Force.

Thanks
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Its the amount of force a man can exert before going 'knnnnnn' the next level up is going '1, 2, 3, hurrrghh' and below is 'ooft'


However, kn actually means Kilo newtons, ie; a thousand newtons

so does that mean if a loco states 500KN it means it can drag 500 newtons or am I completely wrong.

 

[Domh245]

It means that It can provide 500,000 Newtons of Force. 500 Newtons is about 5Kg, and a train that can only drag 5Kg is a bit on the useless side

 

[gazthomas]

I agree

A modern day class 47 if you will!

 

[edwin_m]

It means that It can provide 500,000 Newtons of Force. 500 Newtons is about 5Kg, and a train that can only drag 5Kg is a bit on the useless side

500 newtons (small N) is enough to lift 50kg (small k). So it would pull the skin off a rice pudding but would struggle to lift a sack of potatoes.

 

[Emblematic]

It means that It can provide 500,000 Newtons of Force. 500 Newtons is about 5Kg, and a train that can only drag 5Kg is a bit on the useless side

Close but no cigar - 1 Newton is roughly 0.102 kilogram-force, making 500 newtons about 51 kgf. 500 kN is approx. 51 ton-force.

Beaten to it

 

[Domh245]

Oops. That doesn't bode well for my mechanics exam tomorrow!

 

[SansPareil]

I would have thought there was a good chance of the 68s turning up on occasion on the Sugarliner and Tesco trains between Daventry and Tilbury, some of which I believe run via the GOBLIN.

 

[GatwickDepress]

Will the 68s ever end up on railtour duty?

500 newtons (small N) is enough to lift 50kg (small k). So it would pull the skin off a rice pudding but would struggle to lift a sack of potatoes.

Made me hungry for a rice pudding now...

 

[RichmondCommu]

I would have thought there was a good chance of the 68s turning up on occasion on the Sugarliner and Tesco trains between Daventry and Tilbury, some of which I believe run via the GOBLIN.

A quick question, what is the Sugarliner? I've never come across that term before

 

[SansPareil]

A quick question, what is the Sugarliner? I've never come across that term before

It's an intermodal train that conveys a large amount of 20ft tank containers of presumably sugar. Think they must be quite heavy as there's usually one container per wagon. Not sure of it runs from Tilbury or Purfleet, possibly it can run from either?
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Just to add there are quite a few videos on youtube and photos on flickr;

https://www.youtube.com/watch?v=3bUDuNmZOgA

 

[Boothby97]

Will the 68s ever end up on railtour duty?

Think they will do, there is currently one booked http://www.pathfindertours.co.uk/index.php/tour-calendar-reader/events/the-caterpillar-cat.html


Thanks, Sam

 

[DownSouth]

A modern day class 47 if you will!

With over twice the tractive effort, it will be even better than a pair of Class 47s!

 

[Emblematic]

With over twice the tractive effort, it will be even better than a pair of Class 47s!

Not quite, the quoted tractive effort is 317kN for the 68, around 25% gain on a 47.

 

[ac6000cw]

With over twice the tractive effort, it will be even better than a pair of Class 47s!

Wikipedia rates the 47s as 245 - 267 kN maximum tractive effort, versus 317 kN for the 68 ? (which feels about right for an old 6-axle versus modern 4-axle loco)

As a bit of trivia, I think a Western (class 52 diesel-hydraulic) was the highest tractive effort 'classic' BR diesel loco - just under 300 kN ?

 

[Photohunter71]

Will there be a 68 tour round Scotland at some stage?

 

[tadhatter]

From my experience the vast majority if not all of the intermodal freight running through North London tends to be in the hand of Freightliner. In which case I would suggest that the appearance of DRS locos is likely to be limited. Just saying!

Really? Must have changed a fair bit since I lived in Leyton less than 5 years ago then as my photographs seem to suggest otherwise. Whilst the majority of freight through north london on both NLL and Goblin was Freighliner (including the Shanks waste 66522) there were plenty of GBRf and DRS flows. Although a surprisingly limited number of EWS (before it was DBS) they were involved in various building and construction flows for the Olympic Park.

 

[talltim]

Havent got a clue but what I do know is a 4 axle loco will struggle in low adhesion scenarios no matter how clever the electronic bits are at controlling the wheelslip.

What is the route availability of these locos?
Is it 6 or 7?

So these 68 thingys are medium weight freight locos which will also haul passenger trains then! Potayto potahto!

Well no. If they were just freight locos they wouldn't have ETS.

 

[electrolux]

It means that It can provide 500,000 Newtons of Force. 500 Newtons is about 5Kg, and a train that can only drag 5Kg is a bit on the useless side

Forget it I don't get it

 

[Peter Sarf]

Wikipedia rates the 47s as 245 - 267 kN maximum tractive effort, versus 317 kN for the 68 ? (which feels about right for an old 6-axle versus modern 4-axle loco)

As a bit of trivia, I think a Western (class 52 diesel-hydraulic) was the highest tractive effort 'classic' BR diesel loco - just under 300 kN ?

Ah yes the good old Class52 Western Diesel Hydraulic. Mixed traffic too. Built for the Western Regions expresses but also dragged heavy china clay trains over the Devon banks. They were also used on those really heavy stone trains mentioned up thread - their replacements were so inferior that Foster Yeoman ordered their own Class 59 freight locos to cope. Of course Westerns did not have the right AC or DC traction and as for ETH - another era mate. [/bias].

electrolux - Think of newtons this way. If 300kN is 30591kg (that's what the www has told me) then what that means is the force the loco can pull with would be the same force as is needed to LIFT UP a 30591kg weight. Now to me 30591kg does not sound like much (roughly 30.6 metric tonnes/tons) but the point is railway lines are fairly level and with low friction so its easy to pull rather heavy weights along the line.

electrolux - As for where to see the 68s. You will need to go to Marylebone to see the ones used by Chiltern as the theory is that certain locos will be dedicated to that passenger service - they wont often stray off that. For the freight workings I would recommend you travel the short distance to Willesden Junction. There you will find more freight trains and I think it is likely that the DRS working around there will continue down the West Coast mainline completely missing Gospel Oak. This is what many intermodals currently do. You will also find more people interested in the same things as you there.

 

[The Planner]

Rumours that the 68s will start up in Scotland on their own.

 

[GatwickDepress]

Think they will do, there is currently one booked http://www.pathfindertours.co.uk/index.php/tour-calendar-reader/events/the-caterpillar-cat.html


Thanks, Sam

Lovely, thank you for sharing Sam. I'll be at Crewe on the day, so I might end up seeing it.

 

[Beveridges]

Speaking of Westerns on the Stone trains - Did the westerns pair up on 4000-5000 tons like the 56's?

 

[Beveridges]

66s have enough tractive effort to pull a castle down - 400 KN+ if I remember correctly.


Not as much as a 59/60/70/92 obvious but its still one hell of a force.

 

[ac6000cw]

Speaking of Westerns on the Stone trains - Did the westerns pair up on 4000-5000 tons like the 56's?

I don't think so. AFAIK the Westerns had no MU capability, so it would have meant double-crewing (expensive).

 

[overtonchris]

Speaking of Westerns on the Stone trains - Did the westerns pair up on 4000-5000 tons like the 56's?

I used to see the Westerns very regularly through Reading, Newbury, and weekly through Basingstoke in the early - mid 70's and I don't remember ever seeing one doubled on "stones".....I wish I had though!!

 

[ac6000cw]

66s have enough tractive effort to pull a castle down - 400 KN+ if I remember correctly.


Not as much as a 59/60/70/92 obvious but its still one hell of a force.

If you want force, then try one of these - http://www.rrpicturearchives.net/showPicture.aspx?id=2830050 - a GE ES44AC heavy, high tractive effort version (nice picture, but not one of mine).

195 tonnes, ~880 kN starting tractive effort and 4400 hp. And a 'presence' that our stuff just doesn't have (helped by the loud, very deep rumbling noise that the diesel engines produce ).

A pair of those is on the limit for US coupler strength (about 1800 kN) at maximum tractive effort....last time I was in the US I was watching pairs of them used as rear 'helpers' pushing 10000 tonne coal trains upgrade at 15 mph - almost the definition of 'unstoppable force'....

 

[Beveridges]

A pair of Class 70's (Howler's) would produce over 1000 kN and not weigh a great deal more than the ES 44.

That would be more than enough force to pull a fortress down!

 

[ac6000cw]

That would be more than enough force to pull a fortress down!

Yep

A pair of Class 70's (Howler's) would produce over 1000 kN and not weigh a great deal more than the ES 44.

Built by the same company of course (and doubtless sharing similar traction control systems). Actually an ES44AC 'H' loco could produce more tractive effort - the software limit per axle is 155 kN - but it's deliberately restricted overall to keep the in-train forces sensible. Otherwise it can be a bit too easy to push freight cars off the outside of tight curves when pushing hard on the rear of trains....

(As a relative size comparison, this video - http://www.youtube.com/watch?v=czF7n0umETo - taken at the GE test track is a bit of light entertainment).

I wonder if the Class 70 is tractive effort limited in the same way due to coupler limits - anyone know what the UK screw coupler strength is ?