Question regarding turning Class 68 engines off

[ac6000cw]

EMD FL9: An old design using third rail as well as diesel. ( Think class 73)
GE Genesis P32AC-DM: From what i can read this is a standard diesel electric loco.
EMD DM30AC: Third rail and diesel. Again think class 73
.

The GE Genesis P32AC-DM is the same arrangement as the other two - a diesel with added 3rd rail capability, specifically for working into the NYC main stations. The more powerful P40 & P42 versions are diesel only.

Getting back to the Marylebone problem, is there any sensible-cost possibility to modify the 68s to take power for their auxiliary systems (air compressor, engine heating & coolant circulation, battery charging, electronics etc.) from the ETS supply coming from the genset in the DVT when that is running? Could this allow for a shortened 'main engine start' to departure time?

(The above idea is a variation of the 'hot start' systems that are common on freight locos in some other countries like the US, either by starting the main engine automatically - after ringing warning bells - when air reservoir pressure/engine temperature/battery voltage etc. get too low, or by having a small auxiliary diesel engine that runs to keep everything 'warm & ready' as needed.)

 

[jopsuk]

it would take a more learned person to say for sure, but regardless of whether the DVT genset produces enough power to do it, I'd have thought it possible that the load would be beyond what the ETS cables are specified to take.

 

[SpacePhoenix]

Would it be worth installing a shore supply at Marylebone to power the required bits in the loco (compressors, etc) instead of the auxiliary supply from the DVT (is the auxiliary supply a small engine or batteries?)? Does the hotel power for the coaches currently come from the auxiliary power supply in the DVT?

 

[t_star2001uk]

Would it be worth installing a shore supply at Marylebone to power the required bits in the loco (compressors, etc) instead of the auxiliary supply from the DVT (is the auxiliary supply a small engine or batteries?)? Does the hotel power for the coaches currently come from the auxiliary power supply in the DVT?

A shore supply at Marylebone is impractical due to the relatively short turnaround times of the sets. The compressor on the loco is fed from the alternator supply from the loco only and not from the ETS supply. Under normal running conditions the loco will supply all of the power needs for the set, but if there is an extended amount of downtime at Marylebone the GENSET will be used for hotel power on the trainset only. If the GENSET is used the ETS electronics on the 68 must be in isolate..

 

[najaB]

A shore supply at Marylebone is impractical due to the relatively short turnaround times of the sets...

Thanks for confirming what we had suspected to be the case.

Another consideration when proposing that the 68s shutdown at Marylebone is that diesel engines have their greatest impact on air quality when starting up. So unless the layover was quite long you would be trading air quality for noise reduction.

Not to be obstructive, but noise pollution only affects the residents in the immediate vicinity vice air quality which affects everyone downwind.

So I think the OP's efforts should be focused on better soundproofing and noise barriers (which don't have to be hard barriers).

 

[NickBucks]

Okay so we build a brand new station under Lords cricket ground with the most efficient exhaust extractors available and create new tunnels for enhanced capacity. Jubilee line diverted to serve for onward connections. Class 68s would stop in the Hampstead tunnel so avoiding noise for local residents. Marylebone demolished and new exclusive flats built on the site. Any investors out there wanting to contribute?

 

[NickBucks]

Sorry forgot to mention that the venting shafts would emerge a) in the middle of the Long Room and b) between cover and the boundary.

 

[putabidin]

Another consideration when proposing that the 68s shutdown at Marylebone is that diesel engines have their greatest impact on air quality when starting up. .

The start-up is only a few seconds whereas the idling is 17-29 minutes. I suspect that 1 minute idling produces more pollution than start-up. I have absolutely no quantitative proof of this and stand to be corrected.

Having said that, you are right. The air pollution is a seperate and more important consideration. This thread has taught me that there is very little we can do about it. The only answer is electrification and that's not going to happen for many years, if at all.

There may be some filters which can be fitted to the DMUs and 68s to reduce this. Any thoughts on that, please?

 

[SpacePhoenix]

When 68s have been idling for more then a certain amount of time, does the onboard computer shutdown some of the pistons (rotating which ones get shutdown)?

 

[najaB]

This thread has taught me that there is very little we can do about it. The only answer is electrification and that's not going to happen for many years, if at all.

It's probably more accurate to say that there are many very little things you can do, rather than one 'big bang' solution.

Soundproofing your homes, hard and soft noise barriers, small changes to operational procedures and yes, possibly improved mufflers on the locos can all add up to make a big difference.

 

[TimboM]

Having said that, you are right. The air pollution is a seperate and more important consideration. This thread has taught me that there is very little we can do about it. The only answer is electrification and that's not going to happen for many years, if at all.

I know it's been mentioned before, but whilst electric trains would address the (local) air pollution issue, there would then be visual pollution (from masts/wires) - and if you've ever stood near something like a Class 91 or 92 starting up, they aren't particularly quiet! ...or you get annoying whirring noises like the Class 350 Desiros make. Not sure you can ever completely remove the impact of living near a major railway station/line unfortunately. Good luck in changing the things you can, though.

 

[putabidin]

When 68s have been idling for more then a certain amount of time, does the onboard computer shutdown some of the pistons (rotating which ones get shutdown)?

Certainly there are occasions when we have noticed the level of noise suddenly drops. Doesn't happen every time. Maybe your suggestion above is the reason. As laymen we don't know the reason. Just wish it happened more often.

 

[D365]

When 68s have been idling for more then a certain amount of time, does the onboard computer shutdown some of the pistons (rotating which ones get shutdown)?

What the devil are you on about? You can't do a "partial shutdown" of an engine.

 

[najaB]

What the devil are you on about? You can't do a "partial shutdown" of an engine.

You can, however, stop the fuel to some of the cylinders. Lots of engines do this.

 

[ac6000cw]

Yes you can (in terms of deactivating cylinders) but it has to be designed into the engine so that the 'idle' cylinders don't just pump air around into the exhaust system.

See http://www.jdpower.com/cars/articles/tips-advice/engine-cylinder-deactivation-saves-fuel

 

[Domh245]

What the devil are you on about? You can't do a "partial shutdown" of an engine.

https://en.wikipedia.org/wiki/Variable_displacement

 

[D365]

Apologies, I meant to specify that I'm sure this hasn't been done on a British locomotive.

 

[coppercapped]

Apologies, I meant to specify that I'm sure this hasn't been done on a British locomotive.

I have read (sorry - can't at the moment find the reference) that after a certain time (10 mins?) of idling the MTU4000 engines in the HSTs cut out a number of cylinders to reduce fuel burn and reduce emissions. The engine management computer then cycles the active cylinders around the engine every few minutes to keep the block equally warm.

 

[najaB]

I have read (sorry - can't at the moment find the reference) that after a certain time (10 mins?) of idling the MTU4000 engines in the HSTs cut out a number of cylinders to reduce fuel burn and reduce emissions. The engine management computer then cycles the active cylinders around the engine every few minutes to keep the block equally warm.

I've read that as well but can't find a reference either.

 

[putabidin]

What the devil are you on about? You can't do a "partial shutdown" of an engine.

Nonetheless, there are times that the 68s idle at a different and "slower" speed.

As I said, it doesn't happen often but is a blessed relief when it does.

 

[t_star2001uk]

Nonetheless, there are times that the 68s idle at a different and "slower" speed.

As I said, it doesn't happen often but is a blessed relief when it does.

With regards to the partial shutdown, or shutting down cylinders whilst idling, i have been through all 3 manuals that i have and can find no reference to this. Idle spee without ETS running is 600rpm when the ETS is on i believe that it is 650 to 700 rpm but i will confirm that tomorrow.

Just checked the idle speed and the rusults are 600rpm with no ETS and 1150rpm with ETS ON.

 

[putabidin]

Just checked the idle speed and the rusults are 600rpm with no ETS and 1150rpm with ETS ON.

If the train is in the station for, say, 25 minutes and there is no switch off instruction, I thought that the ETS is not running? As I understand it the two can't be on at the same time. I think you are saying otherwise.

Why would they be needed at the same time?

 

[SpacePhoenix]

With regards to the partial shutdown, or shutting down cylinders whilst idling, i have been through all 3 manuals that i have and can find no reference to this. Idle spee without ETS running is 600rpm when the ETS is on i believe that it is 650 to 700 rpm but i will confirm that tomorrow.

Just checked the idle speed and the rusults are 600rpm with no ETS and 1150rpm with ETS ON.

What's ETS short for?

 

[t_star2001uk]

If the train is in the station for, say, 25 minutes and there is no switch off instruction, I thought that the ETS is not running? As I understand it the two can't be on at the same time. I think you are saying otherwise.

Why would they be needed at the same time?

The ETS on the loco is switched off at Marylebone when someone turns it off. The RPM figures are for the loco only showing the difference between ETS ON and ETS OFF..

 

[t_star2001uk]

What's ETS short for?

Electric Train Supply

 

[najaB]

If the train is in the station for, say, 25 minutes and there is no switch off instruction, I thought that the ETS is not running? As I understand it the two can't be on at the same time.

You're thinking of the separate generator in the DVT which supplies the ETS load when the locomotive isn't running. If the lights and heating/AC are on then something is providing the ETS - either locomotive or generator. As you said, it can't be both.

What t_star2001uk said is that the idle speed of the locomotive is higher when it's supplying the ETS load than when it isn't.

 

[putabidin]

The ETS on the loco is switched off at Marylebone when someone turns it off. The RPM figures are for the loco only showing the difference between ETS ON and ETS OFF..

Sorry, it's my ignorance but I don't understand.

Why is the ETS needed?

Why is it not possible for instuction to be given to turn off the ETS on arrival, and leave the loco running, thereby halving the noise and vibration whilst idling?

 

[najaB]

Why is the ETS needed?

As per above - the ETS load consists of lighting and heating/AC among other things. The cleaners need to be able to see what they are doing if nothing else.

 

[rebmcr]

Why is it not possible for instuction to be given to turn off the ETS on arrival, and leave the loco running, thereby halving the noise and vibration whilst idling?

It's quite possible that more low-frequency sound is emitted when at a lower RPM. You might wish to arrange some time with Chiltern to sample the different modes and establish for sure which is least intrusive.

 

[putabidin]

As per above - the ETS load consists of lighting and heating/AC among other things. The cleaners need to be able to see what they are doing if nothing else.

And these functions rely on the ETS load and there would be no light and heat if ETS turned off, even if loco was idling?

Sorry to be dense.

Perthaps you'd be kind enough to explain in laymans terms the relationship between DMU,ETS and locomotive power as they relate to each other and to the "hotel" services.