GBRF class 66 re-gearing

[SWR450127]

66793 has now been converted to 66693 and is currently working 0E70 Longport - Peterborough.

 

[ethanswr159]

Someone told me that 66793 has already been renumbered at 66693 but I'm unsure whether or not this is true as I've seen nothing on it. Can anyone confirm whether this is actually true or not.

 

[47476NightMail]

Someone told me that 66793 has already been renumbered at 66693 but I'm unsure whether or not this is true as I've seen nothing on it. Can anyone confirm whether this is actually true or not.

66793 continues to show as such on TOPS this morning. 66689 remains the only change at the time of writing.

EDIT: Just released from Longport and working 0L60 to Whitemoor as 66693 (along with 66772).

 

[Trainz6013]

Just seen this by railadvent:

GB Railfreight modifying 12 Class 66s

Freight operator GB Railfreight (GBRf) is modifying 12 of its Class 66s with different gear ratios to enable them to increase their power output. Freight operator GB Railfreight (GBRf) is modifying 12 of its Class 66s with different gear ratios to enable them to increase their power output.

www.railadvent.co.uk

 

[cj_1985]

So is it 12 total... or 'ANOTHER' 12

 

[Nym]

Just seen this by railadvent:

GB Railfreight modifying 12 Class 66s

Freight operator GB Railfreight (GBRf) is modifying 12 of its Class 66s with different gear ratios to enable them to increase their power output. Freight operator GB Railfreight (GBRf) is modifying 12 of its Class 66s with different gear ratios to enable them to increase their power output.

www.railadvent.co.uk

"Different gear ratios to increase their power output."

I know I've come to not expect much these days from any press organisation, but a basic understanding of what a gearbox actually does on a railway press org would be reasonably expected? No?

Context:
Gearboxes are a 'constant-power' device, assuming no losses.

Even if there are losses accounted for here, higher ratio gears tend to be less efficient, so this would if anything, "Reduce" the power of the locomotive.

 

[hwl]

"Different gear ratios to increase their power output."

I know I've come to not expect much these days from any press organisation, but a basic understanding of what a gearbox actually does on a railway press org would be reasonably expected? No?

Context:
Gearboxes are a 'constant-power' device, assuming no losses.

Even if there are losses accounted for here, higher ratio gears tend to be less efficient, so this would if anything, "Reduce" the power of the locomotive.

Agreed basic rail engineering literacy is attrocious these days. This is all about getting better TE at low and medium speeds due to the DC motors having a more optimal voltage/current combination thrown at them at a given speed (at low / medium speeds, less optimal at higher speeds) compared to a 75mph geared version.
Tenuously if they deliver more TE and hence power at the rail at a given speed you could claim to have increased the power output, but they haven't clarified what they mean by "power".
There isn't too much difference in gear efficiency between the two.

 

[Wyrleybart]

I am guessing you know what it means but are having a go at the journalists who wrote it.

As I understand GBRf already have four "66/6", but not sure if locos were like it in Germany / Holland, and have been converted when they were delivered to Loughborough.

So I am also assuming GBRf have kits for another eight conversions from the fleet, making it 12 66/6 in total. Still think they need to convert 66756 to make it 66666 !!!

 

[cj_1985]

I am guessing you know what it means but are having a go at the journalists who wrote it.

As I understand GBRf already have four "66/6", but not sure if locos were like it in Germany / Holland, and have been converted when they were delivered to Loughborough.

So I am also assuming GBRf have kits for another eight conversions from the fleet, making it 12 66/6 in total. Still think they need to convert 66756 to make it 66666 !!!

AIUI 2x were delivered as /6 spec and the other two were converted by EMSI here

 

[ac6000cw]

I am guessing you know what it means but are having a go at the journalists who wrote it.

Quite rightly too - the difference and relationships between mass, force (tractive effort in this context), power, energy etc. are some of the most basic things in science, and something we all experience all the time in our daily lives (e.g. Isaac Newton's 'falling apple'). That's why it's taught in schools - and if someone doesn't know/can't remember, it's never been easier/quicker to find out information on a subject than it is now.

 

[Nym]

Correct. This is basic GCSE science…(!)

 

[train_lover]

66793 has now been converted to 66693 and is currently working 0E70 Longport - Peterborough.

66793 was already a low geared 66 along with 66794 795 and 796. They'd frequently catch me out when I'd lose power at 65mph

 

[The_Train]

"Different gear ratios to increase their power output."

I know I've come to not expect much these days from any press organisation, but a basic understanding of what a gearbox actually does on a railway press org would be reasonably expected? No?

Context:
Gearboxes are a 'constant-power' device, assuming no losses.

Even if there are losses accounted for here, higher ratio gears tend to be less efficient, so this would if anything, "Reduce" the power of the locomotive.

Rail Advent just regurgitate other press releases

Edit: Not knocking them for that as it's handy to have all of such things in one place but they certainly are not responsible for these issues, that will have (sadly) come from people who should know and produce better

 

[Richard Scott]

Agreed basic rail engineering literacy is attrocious these days. This is all about getting better TE at low and medium speeds due to the DC motors having a more optimal voltage/current combination thrown at them at a given speed (at low / medium speeds, less optimal at higher speeds) compared to a 75mph geared version.
Tenuously if they deliver more TE and hence power at the rail at a given speed you could claim to have increased the power output, but they haven't clarified what they mean by "power".
There isn't too much difference in gear efficiency between the two.

You may get more power at lower speeds as you are unlikely to be able to load the motors to maximum at a standing start so power at 0mph will be limited to less than rated continuous power output, which is probably available from around 10mph+.

 

[JKF]

DB were using their 66/6s frequently on the Portbury steel flows (after regular locos struggled getting up the hill out of the docks in the Autumn). GBRF are now running that flow, so perhaps one where a stronger 66 would allow more wagons or be more resilient once the leaves start coming down. I think their trains have been shorter than what DB was running.

 

[800001]

How many Gbrf 66w have now been renumbered? TIA

 

[Spaceship323]

How many Gbrf 66w have now been renumbered? TIA

Only 2 so far: 66689 (66779) and 66693 (66793)

 

[800001]

Only 2 so far: 66689 (66779) and 66693 (66793)

Thank you

 

[Incogcyclist79]

66687 has now been released. Through Stone at 16:00 working 0E70 15:35 Longport to Peterborough GBRF Depot.

 

[DBS92042]

66687 has now been released. Through Stone at 16:00 working 0E70 15:35 Longport to Peterborough GBRF Depot.

The former 66777?

 

[SWR450127]

The former 66777?

Correct.

 

[The_Train]

The former 66777?

Why has 66777 become 66687 instead of 66677?

In the grand scheme of things it doesn't matter, but it's intrigued me

 

[Spaceship323]

I Think DB had 66661 - 66670 so GBRf started at 66681 to keep the numbers non-sequential - maybe. (Or perhaps GBRf are numbering down from 66699?)

 

[wickham]

I Think DB had 66661 - 66670 so GBRf started at 66681 to keep the numbers non-sequential - maybe. (Or perhaps GBRf are numbering down from 66699?)

In truth, the GBRf renumbering is a bit of a mess, I can see the logic, but it would have been much neater to renumber to 6667xx (in order of completion) thereby retaining the GBRf "identity 7", although in a different place in the number (4th digit vice 3rd digit) - a shame that DB got there first with 66670 !!

 

[CR165022]

In truth, the GBRf renumbering is a bit of a mess, I can see the logic, but it would have been much neater to renumber to 6667xx (in order of completion) thereby retaining the GBRf "identity 7", although in a different place in the number (4th digit vice 3rd digit) - a shame that DB got there first with 66670 !!

The DB 66/6s are 66651-660, not to 670

 

[JKF]

They seem to be consciously avoiding 66666 for some reason, which I find a bit disappointing as it rules out making ‘Number of the Beast’ jokes.

I think the original DB plan was to convert 16 but they’ve pulled the plug (apparently) at 10.

 

[43096]

They seem to be consciously avoiding 66666 for some reason, which I find a bit disappointing as it rules out making ‘Number of the Beast’ jokes.

I think the original DB plan was to convert 16 but they’ve pulled the plug (apparently) at 10.

The original plan was 10, which was extended to 15 (with 66651-665 reserved), but 66661-665 are no longer reserved for DB, indicating that the final five conversions have been cancelled.

 

[Tunnel Bore]

Agreed basic rail engineering literacy is attrocious these days. This is all about getting better TE at low and medium speeds due to the DC motors having a more optimal voltage/current combination thrown at them at a given speed (at low / medium speeds, less optimal at higher speeds) compared to a 75mph geared version.
Tenuously if they deliver more TE and hence power at the rail at a given speed you could claim to have increased the power output, but they haven't clarified what they mean by "power".
There isn't too much difference in gear efficiency between the two.

In this context, power can only mean one thing and that is the rate at which work is done and is measured in joule/second (J/s) or watt (W or kW or MW).

Tractive effort is a force at the drawbar in newton (N or kN) or a torque on a shaft in newton metre (Nm or kNm).

To get the power you multiple force (N) x velocity (m/s) = power (W) or torque (Nm) x angular velocity (rad/s) = power (W). [There are 2 pi radians in one revolution].

If you use a gearbox to gear down to produce a slower speed for a given motor speed the torque goes up ideally by the same ration yielding the same power but in reality (and the presence of friction) a slightly lower ratio and a slight loss of power.

If you deliver an increased TE at the same speed, by gearing down, it can only be that the tractions motors are spring faster than they previously were and delivering more power.

 

[Richard Scott]

If you deliver an increased TE at the same speed, by gearing down, it can only be that the tractions motors are spring faster than they previously were and delivering more power.

They won't be as although spinning faster their force is reduced by fact back emf is higher so current is lower, therefore power output, in theory, is identical to a higher geared loco. The only point that won't be true is low speed where it's not possible to get maximum rail power due to current limitations, which is where the lower geared machine wins.
At higher speeds reverse is true and higher geared machine will be able to maintain full power at higher speeds.

 

[hwl]

If you deliver an increased TE at the same speed, by gearing down, it can only be that the tractions motors are spring faster than they previously were and delivering slightly more power torque at the same speed.

Not quite I have amended. The power is limited by what comes out of the alternator terminals albeit the voltage/current combination thrown at the TMs by the alternator will be slightly different resulting in the need to do a bit of relearning for driver which is probably what is giving DB nightmares at the moment (and FL staff breaking out the popcorn).
I may do an explainer with graphics and data on this at some point if I get the time.

They won't be as although spinning faster their force is reduced by fact back emf is higher so current is lower, therefore power output, in theory, is identical to a higher geared loco. The only point that won't be true is low speed where it's not possible to get maximum rail power due to current limitations, which is where the lower geared machine wins.
At higher speeds reverse is true and higher geared machine will be able to maintain full power at higher speeds.

Mostly agreed but due to subtle difference in the voltage and current supplied by the alternator to the TMs at a given speed compared to 75mph geared locos the TE deliverable at low-medium non-adhesion limited speeds is slightly better (small single digit %) due to very slightly better motor efficiency.
The solution to the back EMF issue is three phase motors driven by VVSD operating at a high voltage as possible with gearing that is vaguely appropriate for the max top speed, the tolerance on gearing ratio choice is much wider.

The parallel to series-parallel switch over speed is also lower on the 65mph geared locos to align with the different V/I characteristics.