Question regarding turning Class 68 engines off

[Clip]

Between 7.28 and 18.18 there are 14 of these.

In that 11 hours only 4 shutdown. The rest idle for between 16 and 23 minutes each.

.

Out of interest but how many residents are home during these prime working hours?

 

[putabidin]

I sympathise with putabidin and his fellow residents - those things make some serious noise/vibrations!

Thanks for the sympathy. Imagine that as a noise/vibration lasting for 16-23 minutes.

Sixteen times a day.

Now you realise why are desperate to find ways of reducing and, eventually, eliminating it.

 

[putabidin]

It's also worth noting that the 165s will be pushing 30 years old by the end of the current franchise, so I would guess new trains will be on the cards for the replacement franchise.

We are terrified that the 68s will proliferate on this line.

What are the alternatives for the shorter, non-Birmingham routes. eg Aylesbury, Gerrards Cross etc.

Please give me hope that there are more modern, less polluting, less noisy replacements which will do the trick.

 

[TheEdge]

Please give me hope that there are more modern, less polluting, less noisy replacements which will do the trick.

Oh dear.

Explain to me again how the UKs newest locomotives are not modern? They are barely 4 years old, they've easily got another 30 years in them yet.

 

[87015]

We are terrified that the 68s will proliferate on this line.

What are the alternatives for the shorter, non-Birmingham routes. eg Aylesbury, Gerrards Cross etc.

Please give me hope that there are more modern, less polluting, less noisy replacements which will do the trick.

As said a few times already in this thread, they are louder particuarly because they are less polluting. The emission reduction equipment reduces the space available for a silencer.

 

[putabidin]

Oh dear.

Explain to me again how the UKs newest locomotives are not modern? They are barely 4 years old, they've easily got another 30 years in them yet.

Oh dear. You didn't read the full text. I'll make it clearer.
.........Than the 165s.

What is the modern alternative to these that will not involve running such a powerful and noisy loco as the 68?

 

[TimboM]

We are terrified that the 68s will proliferate on this line.

What are the alternatives for the shorter, non-Birmingham routes. eg Aylesbury, Gerrards Cross etc.

Please give me hope that there are more modern, less polluting, less noisy replacements which will do the trick.

Knowing your luck, it'll be some cascaded shortened HST sets - with a noisy diesel loco at BOTH ends

 

[putabidin]

As said a few times already in this thread, they are louder particuarly because they are less polluting. The emission reduction equipment reduces the space available for a silencer.

I hear what you say but I am concerned about Marylebone residents.

In the 10 minute idling time of a DMU set versus the 22 minutes of a Class 68,
which is more polluting?

Certainly the visible emissions would indicate the latter.

 

[GW43125]

I hear what you say but I am concerned about Marylebone residents.

In the 10 minute idling time of a DMU set versus the 22 minutes of a Class 68,
which is more polluting?

Certainly the visible emissions would indicate the latter.

If you think DMUs don't pollute, you clearly haven the seen one giving it the beans...

 

[tomuk]

As there is a generator in the DVT supplying ETS to the train. Could this not be used to power a water heater and an electric compressor fitted in the 68 to allow the startup time to be reduced.

 

[D365]

Oh dear. You didn't read the full text. I'll make it clearer.
.........Than the 165s.

You didn't make it clear that you were asking about the Class 165s.

And there aren't really any "modern alternatives" because nobody's put an order in.

 

[najaB]

As there is a generator in the DVT supplying ETS to the train. Could this not be used to power a water heater and an electric compressor fitted in the 68 to allow the startup time to be reduced.

All things are possible with a suitable supply of money and time, but that's some pretty major surgery you're proposing. I don't imagine it would be cheap.

 

[putabidin]

If you think DMUs don't pollute, you clearly haven the seen one giving it the beans...

Yes, the DMUs emit but,
I can only go by what I see from my flat overlooking the platforms. The DMUs (in theory) shut down if they are staying more than 10 minutes. Whilst idling there seems to be little particulate emission that is visible to the naked eye. I am sure there is some. When they move out there is a very dense cloud of "smoke" (is that ""giving it the beans"?) and off they go.

The 68s only shut down if they are in for over about 23 minutes. Whilst idling there are visible emissions (not dense, but visible) and when they go out there is a dense cloud similar to that from the DMUs.

I have no knowledge which will tell me whether the emissions from the 68 are filtered and less harmful, but everything I observe leads me to believe that the 68s are responsible for as much or more emissions than the DMUs...as far as being inside the station limits is concerned.

Whether that is true when they are running, I have no idea.

Happy to be corrected if I am wrong.

There are, of course, many more DMU movements in the course of a day.

 

[najaB]

Yes, the DMUs emit but,
I can only go by what I see from my flat overlooking the platforms.

The harmful emissions are invisible. The stuff you can see is mostly carbon (soot basically).

 

[D365]

The Class 68s were built to comply with the far more recent emissions standards so they really shouldn't be causing more pollution.

 

[putabidin]

The harmful emissions are invisible. The stuff you can see is mostly carbon (soot basically).

Ah. I see. Ignorant of me.

Are the harmful emissions therein, or do they have a seperate outlet?

I believe there is growing pressure for a new Clean Air Act to catch carcingenic emissions.. I suppose railways will be exempt.

 

[najaB]

Ah. I see. Ignorant of me.

Are the harmful emissions therein, or do they have a seperate outlet?

No, they are mixed in with the exhaust. The black stuff you can see is largely carbon (soot) as per above. It isn't nice to breath in, but it'll either get filtered out on the way down by your nose hairs and nasal mucous, or trapped by the mucous in your respiratory tract and dealt with by the body.

The harmful stuff is the very small particulates (also carbon but too small to see) which get deep into your lungs where the body has a hard time getting rid of them, nitrous oxides (NOX) and various organic molecules (benzene, formaldehyde, etc.)

 

[87015]

Ah. I see. Ignorant of me.

Are the harmful emissions therein, or do they have a seperate outlet?

I believe there is growing pressure for a new Clean Air Act to catch carcingenic emissions.. I suppose railways will be exempt.

You need to separate noise and emissions, which you have now moved on to. The issues are separate, and as has repeatedly been said, one tends to trade off against the other.

It's nothing to do with the railway being exempt, the 68s are part of a reduction in emissions. Most of the Chiltern DMUs were not built to the emission standards that 68s meet, if you are not going to accept this and go off visible emissions I suggest getting some professionals in to see what the picture actually is on the ground.

 

[putabidin]

You need to separate noise and emissions, which you have now moved on to. The issues are separate, and as has repeatedly been said, one tends to trade off against the other.

Yes, I would like to move on to emissions, but bear in mind the need to keep noise down as much as possible.

When the DMUs are replaced I don't (on the grounds of noise) want them replaced with 68s if it can be avoided.

Will it really be necessary to use these powerful, mixed traffic locomotives for the shorter runs currently undertaken by the DMUs?

Currently, London/Birmingham is time and service sensitive versus Virgin, hence the justification for the 68s.

Do you know of alternatives which give out lower emissions than the DMUs but will still do the job over the shorter, less time sensitive runs?

 

[TimboM]

Do you know of alternatives which give out lower emissions than the DMUs but will still do the job over the shorter, less time sensitive runs?

Erm... EMUs! ...but then we're back to the electrification point.

 

[coppercapped]

Yes, I would like to move on to emissions, but bear in mind the need to keep noise down as much as possible.

When the DMUs are replaced I don't (on the grounds of noise) want them replaced with 68s if it can be avoided.

Will it really be necessary to use these powerful, mixed traffic locomotives for the shorter runs currently undertaken by the DMUs?

Currently, London/Birmingham is time and service sensitive versus Virgin, hence the justification for the 68s.

Do you know of alternatives which give out lower emissions than the DMUs but will still do the job over the shorter, less time sensitive runs?

Some more background.

The DMUs date from different periods, the oldest being the Class 165s which date from 1990-92. There was then a gap until privatisation when Chiltern Railways ordered a variant of the 165 called the 168 which were delivered from 1998. Since then small batches of later models have been added.

Each of the carriages of these trains are fitted with a diesel engine of between 350bhp and 450bhp depending on the model. The earlier trains were built before any regulations concerning emissions applied to the railways but now all new designs have to meet the emission standards of the EU Off Road Machinery directive. The current level is called Euro Stage IIIB. I suggest that you research this document. I don't think any of the later builds of DMUs meet IIIB but some might meet the earlier Stage IIIA standard.

Manufacturers such as MAN and MTU who supply underfloor power units for railcars both have engines which meet the IIIB regulations. Any future DMUs are legally required to meet this regulation. If you find that this standard is still not satisfactory for your situation your only recourse is to the European Commission although I would point out that stricter regulations are in the pipeline.

For high power diesel locomotives such as the Class 68 the dimensions of the exhaust gas treatment equipment means that with the constraints of the British structure gauge and with the current level of technology, it is not possible to meet the IIIB requirements with a diesel engine having a power output above about 3,000bhp. Railways elsewhere in the world with larger structure gauges have less of a problem. The Class 68 has a power output of some 3,800bhp and meets the earlier, then current, standard Stage IIIA.

So, it seems you have two issues. One is the level of exhaust emissions from the DMUs and the other is the level of exhaust emissions and the noise level of the idling locomotives.

The choice between DMU and locomotive operation depends on the type of service the trains operate. Locomotive hauled trains become more economic than DMUs if the train length is six or more carriages long and remains at this length all day. This is largely because maintaining one large prime mover is less costly than looking after six or more in one train. DMUs have the advantage that if the train length is varied during the day the train's power-to-weight ratio remains constant - because each carriage is powered. Running a short locomotive hauled trains is uneconomic because under these conditions the power level is excessive and at short stations the locomotive removes possible passenger capacity for the same length of train. (There are however some workrounds which ameliorate the situation somewhat).

When the time comes to replace the existing DMUs they will be replaced by new-build DMUs meeting whatever emissions regulations are then in force. The DMUs will not be replaced by locomotive hauled sets - but there is no reason that the opposite cannot happen.

A theoretical possibility exists to replace the engines under the existing DMUs by more modern units - but generally this is not economic because of the extent of the work needed which has to be amortised within the remaining life of the vehicle.

At the moment there is no possibility of reducing the level of exhaust emissions from the locomotives of this power level as the kit will not fit into the body. Using a lower powered locomotive does not make any commercial sense as then the train performance will suffer. Noise barriers work to an extent for line-of-sight sound transmission but are much less effective at low frequencies where the sound wavelength is larger than the barrier dimensions so the sound simply diffracts around the edges of the barrier. There will be some benefit - but it is frequency dependent.

Cutting the time that the locomotives idle would seem to be the best approach - but as others have written, as the locomotives are now configured this seems to be difficult. If, at the specification stage, it had been a requirement that the train be ready to move within x minutes of engine start then I'm sure that this could have been done. However the locomotives were built to meet the needs of a freight train operator and the use of these locomotives into Marylebone came later. I suspect that re-working them now would be a very expensive operation - if it's even possible.

Of course if the line is electrified then these issues go away.

 

[KingDaveRa]

Of course if the line is electrified then these issues go away.

Are the tunnels big enough to take it? I remember back in the VERY dim distant past the idea of electrifying the line being mooted, and there being a lot of talk about a lot of infrastructure along the line being too short to take the wires. Whether that also included the tunnels out of MYB, I don't know. That said, the issue still remains, and hundreds of bridges would need modifying potentially.

 

[putabidin]

When the time comes to replace the existing DMUs they will be replaced by new-build DMUs meeting whatever emissions regulations are then in force. The DMUs will not be replaced by locomotive hauled sets - but there is no reason that the opposite cannot happen .

Thank you coppercapped, your explanation has been invaluable. As all you kind contributors realise, I am just Joe Public with no real rail knowledge and relient on your expertise to help see the residents through to a more satisfactory position.

The difference between the use of DMUs and locos is clear now. Also that the 168s that do the Birmingham run can only comprise 4 carriages and so are not suitable for the flagship service needed on this line.

I assume and hope that the choice of a "freight" train to pull the 6 coach Silver Trains was the only one available. I realise the commercial need to provide the fastest possible service to Birmingham was paramount. Unfortunately the residents at Marylebone have to suffer for this decision.

The franchise (and, presumably the contract with DRS) is due for renewal in 2021, does anyone know of an alternative to the 68s which would pull 6 coaches to Birmingham at a good speed without the noise side effect?

Is there an alternative to the 168s which could deliver the 6 carriage solution?

There are 6 carriage DMUs operating on the other lines, might one hope that, when the new franchise comes and the need to replace the older DMUs, we might find a low emission, low noise alternatives to the 68s.

 

[najaB]

The franchise (and, presumably the contract with DRS) is due for renewal in 2021, does anyone know of an alternative to the 68s which would pull 6 coaches to Birmingham at a good speed without the noise side effect?

It's probably 60/40 in favour of any replacement being a new build DMU rather than loco-hauled. There are a few new DMU designs which have come onto the market in the last couple of years that meet the Stage IIIb requirements which they could use instead. That said, they have put a lot of money into refurbishing their loco-hauled carriages so any replacement is unlikely before they have earned their money back on them.

 

[putabidin]

There are a few new DMU designs which have come onto the market in the last couple of years that meet the Stage IIIb requirements

Will Chiltern be forced to replace/refurbish their existing DMU fleet to comply with Stage 111b requirements or does it only apply to replacement by reason of age?

 

[najaB]

Will Chiltern be forced to replace/refurbish their existing DMU fleet to comply with Stage 111b requirements or does it only apply to replacement by reason of age?

No. The rules apply to new stock when it is introduced. Existing stock has to meet the rules that applied when it was introduced.

 

[t_star2001uk]

I assume and hope that the choice of a "freight" train to pull the 6 coach Silver Trains was the only one available.

The class 68 was built as a mixed traffic locomotive and not for just freight. As for suitable alternative that is available now, there are class 67s. Failing that there are quite a few pieces of heritage traction out there as well. And if you think a 68 can have a dirty exhaust, you should see some of the heritage stuff.So short of full electrification I don't think there is a viable alternative to the 68s.

 

[putabidin]

So short of full electrification I don't think there is a viable alternative to the 68s.

Accepted. Nothing we can do at present.

Is there any way that one could say with any degree of certainty that,say, the NOx emissions resulting from 25 minutes of idling by a Class 68 loco were greater or less than that from, say, a 168 or 165 idling for 10 minutes?

If not, does anyone have an opinion?

 

[najaB]

If not, does anyone have an opinion?

I can't say with certainty but the engine used in the Class 168 is likely a Stage 1 engine based on when they were introduced (stage 1 is anything between 1996 and 2001 and the 168s date from 1999 onwards). Stage 1 engines can put out anything up to 9.2 g/kW-hr.

The Class 68 is (afaik) Class 3b. The limit for which is 2.0g/kW-hr.

I have no idea what the power output is of either type of engine while idling, but I doubt the Class 68 engine takes more than 16 times the amount of energy to tick over which is what it would need to do in order to exceed the NOx production of a 168 in half the time.

 

[ac6000cw]

I can't say with certainty but the engine used in the Class 168 is likely a Stage 1 engine based on when they were introduced (stage 1 is anything between 1996 and 2001 and the 168s date from 1999 onwards). Stage 1 engines can put out anything up to 9.2 g/kW-hr.

The Class 68 is (afaik) Class 3b. The limit for which is 2.0g/kW-hr.

I have no idea what the power output is of either type of engine while idling, but I doubt the Class 68 engine takes more than 16 times the amount of energy to tick over which is what it would need to do in order to exceed the NOx production of a 168 in half the time.

The class 68 meets Euro 3a (not 3b), the limit for which is 7.4g/kW-hr for engines of greater than 2000 kW (which the 68 is). See https://www.dieselnet.com/standards/eu/nonroad.php and scroll down to the 'Rail Traction Engines' section at the bottom of the page.