Hitachi trains grounded

[boxbrownie]

12 hours ago, Ramblin Rich said:

Just to add to Hitachi's woes:

Pollution on some new UK trains ‘13 times one of London’s busiest roads’

https://www.theguardian.com/uk-news/2021/sep/16/pollution-on-some-new-uk-trains-13-times-one-of-londons-busiest-roads

 

[Hobby]

All pretty predictable stuff... If you are in a tunnel the fumes have nowhere to go but back into the train, if you are further to the back then you'll get more fumes as the number of powered units in front of you increase... Been the same ever since they brought in DMUs... If you take a road tunnel the same can happen, even on "ventilated" ones, and there's a good reason for that "air recirculation" button on your car dash as anyone stuck in a traffic jam knows... Perhaps there should be a recirculation option for trains as well for when going through long tunnels... TBH I only notice the fumes when inside or exiting tunnels such as Clay Cross or standing next to a unit on the platform, most of the time you can hear them but not smell them!

 

Good argument for electrification or hydrogen power, though.

 

(As virtually all modern trains are now fitted with sealed windows and aircon I'd love to know where "Passengers on trains pulled by diesel locomotives are more exposed to fumes when sitting in rear rather than front carriages, the researchers found, possibly due to the how the exhaust is drawn into the train’s windows " came from, perhaps they surveyed some 156s!)

[Talltim]

5 minutes ago, Hobby said:

All pretty predictable stuff... If you are in a tunnel the fumes have nowhere to go but back into the train, if you are further to the back then you'll get more fumes as the number of powered units in front of you increase... Been the same ever since they brought in DMUs... If you take a road tunnel the same can happen, even on "ventilated" ones, and there's a good reason for that "air recirculation" button on your car dash as anyone stuck in a traffic jam knows... Perhaps there should be a recirculation option for trains as well for when going through long tunnels... TBH I only notice the fumes when inside or exiting tunnels such as Clay Cross or standing next to a unit on the platform, most of the time you can hear them but not smell them!

 

Good argument for electrification or hydrogen power, though.

 

(As virtually all modern trains are now fitted with sealed windows and aircon I'd love to know where "Passengers on trains pulled by diesel locomotives are more exposed to fumes when sitting in rear rather than front carriages, the researchers found, possibly due to the how the exhaust is drawn into the train’s windows " came from, perhaps they surveyed some 156s!)

Railtours?

150, 153, 155, 156, 158 and 159 all have opening windows (of a sort). However they don't tend to be pulled by locos

[boxbrownie]

It also said the measurements were stationary at stations as well, not just tunnels (which would indeed be a bit obvious), it just points to a bit of bad design (or overlooked) in the HVAC intake design.

Edited September 17, 2021 by boxbrownie

[rodent279]

I suspect it's a slow news day, and someone wanted easy copy.

[Hobby]

25 minutes ago, boxbrownie said:

It also said the measurements were stationary at stations as well, not just tunnels (which would indeed be a bit obvious), it just points to a bit of bad design (or overlooked) in the HVAC intake design.

 

Or lack of proper ventilation at some stations, New Street installed some big fans when they did the refurb but thinking about it I haven't heard them used for quite a while now, when they were first installed they were forever going off when a Voyager or 170 came in.

Edited September 17, 2021 by Hobby

[Titan]

"NO2 levels on the two-year-old bi-mode Hitachi trains peaked at more than 13 times the average recorded on the traffic-clogged Marylebone Road"

 

So nowhere near a fair comparison, how does it look when peak is compared to peak, or average compared to average?

[Mark Saunders]

18 minutes ago, Titan said:

"NO2 levels on the two-year-old bi-mode Hitachi trains peaked at more than 13 times the average recorded on the traffic-clogged Marylebone Road"

 

So nowhere near a fair comparison, how does it look when peak is compared to peak, or average compared to average?

Never let statistical analysis spoil a good headline!

[rodent279]

On 17/09/2021 at 12:51, Titan said:

"NO2 levels on the two-year-old bi-mode Hitachi trains peaked at more than 13 times the average recorded on the traffic-clogged Marylebone Road"

 

So nowhere near a fair comparison, how does it look when peak is compared to peak, or average compared to average?

The voltage on the live wire of the mains PEAKS at 325V above the AVERAGE.

Edited September 18, 2021 by rodent279

[corneliuslundie]

But back to the issue actually being highlighted, whether expressed properly or not by the press, it seems that coach AC systems are quite good at circulating exhaust from the engines through the coaches, and aerodynamics means that it happens more further back the train. Even if it is not near danger levels, it is still a significant finding. It would be a good idea if some research could now be done to find the best place for the air intakes to minimise exhaust fumes entering. Not life and death but probably a more pleasant internal environment.

Though I would prefer to open the window!

Jonathan

[Dunsignalling]

15 minutes ago, corneliuslundie said:

But back to the issue actually being highlighted, whether expressed properly or not by the press, it seems that coach AC systems are quite good at circulating exhaust from the engines through the coaches, and aerodynamics means that it happens more further back the train. Even if it is not near danger levels, it is still a significant finding. It would be a good idea if some research could now be done to find the best place for the air intakes to minimise exhaust fumes entering. Not life and death but probably a more pleasant internal environment.

Though I would prefer to open the window!

Jonathan

Not necessarily, and certainly not only aerodynamics, just simple arithmetic.

 

The further back the train you are, the greater the number of exhausts will be discharging ahead of the intakes on your coach.

 

John

[corneliuslundie]

On a slightly different note, I also heard a rumour, again without a source, that the bimodes on the ECML were using diesel more because of lack of capacity in the grid. Is this something new, possibly caused by the French interconnection substation fire, or is it old news stemming from the delayed upgrade of power supplies which was discussed a couple of years ago?

Jonathan

[Welly]

5 hours ago, Talltim said:

Railtours?

150, 153, 155, 156, 158 and 159 all have opening windows (of a sort). However they don't tend to be pulled by locos

I remember in the early 1990s being on a 158 paused in the tunnel just outside Glasgow Queen Street - it filled nicely with diesel fumes!

[Dunsignalling]

I remember when the first Skippers (Class 142) came to the West Country, with the original type doors, when departing from Exeter St Davids, Platform 1, there was a pressure effect caused by the canopy that forced visible exhaust fumes in through the gaps between the door leaves!

 

Some things, I just can't muster any nostalgia for.

 

John  

[rab]

I have two lasting memories of my

one and only sleeper train experience.

 

One was it seemed like whenever

I'd just managed to get to sleep,

the train stopped to pick up more coaches,

the associated banging and jolting waking me up.

 

The other was the constant smell of diesel fumes.

[billbedford]

8 hours ago, corneliuslundie said:

On a slightly different note, I also heard a rumour, again without a source, that the bimodes on the ECML were using diesel more because of lack of capacity in the grid. Is this something new, possibly caused by the French interconnection substation fire, or is it old news stemming from the delayed upgrade of power supplies which was discussed a couple of years ago?

 

It seems to be due to the weather and a lack of gas. Two fertiliser plants have closed down due to a lack of gas today. 

[St Enodoc]

7 hours ago, Welly said:

I remember in the early 1990s being on a 158 paused in the tunnel just outside Glasgow Queen Street - it filled nicely with diesel fumes!

When the 27s were working the E&G push-pulls, Queen Street Tunnel was always full of exhaust fumes.

[jamie92208]

8 hours ago, billbedford said:

 

It seems to be due to the weather and a lack of gas. Two fertiliser plants have closed down due to a lack of gas today. 

Slightly off topic it's due to the high price of gas and the downside is that the UK is now short of Carbon Dioxide.

 

Jamie

Edited September 18, 2021 by jamie92208

[Hal Nail]

17 hours ago, corneliuslundie said:

It would be a good idea if some research could now be done to find the best place for the air intakes to minimise exhaust fumes entering.

Somewhere in the Alps maybe?

[boxbrownie]

19 hours ago, corneliuslundie said:

But back to the issue actually being highlighted, whether expressed properly or not by the press, it seems that coach AC systems are quite good at circulating exhaust from the engines through the coaches, and aerodynamics means that it happens more further back the train. Even if it is not near danger levels, it is still a significant finding. It would be a good idea if some research could now be done to find the best place for the air intakes to minimise exhaust fumes entering. Not life and death but probably a more pleasant internal environment.

Though I would prefer to open the window!

Jonathan

The motor industry cured these issues decades ago, to stop exhaust gases being drawn into a vehicle in motion the HVAC outlets at the rear of a vehicle body has a “one way valve/flap”, this prevents the low pressure area behind a vehicle where exhaust gases are slow to disperse being a source of danger to the occupants. Of course the inlet air is at the front usually below the windscreen plenum chamber.

 

Maybe a complete train is a bit more difficult to wind tunnel analyse 

[PhilJ W]

13 minutes ago, boxbrownie said:

The motor industry cured these issues decades ago, to stop exhaust gases being drawn into a vehicle in motion the HVAC outlets at the rear of a vehicle body has a “one way valve/flap”, this prevents the low pressure area behind a vehicle where exhaust gases are slow to disperse being a source of danger to the occupants. Of course the inlet air is at the front usually below the windscreen plenum chamber.

 

Maybe a complete train is a bit more difficult to wind tunnel analyse 

The problem is that the majority of trains are bi-directional and a lot longer than a car.

[boxbrownie]

4 minutes ago, PhilJ W said:

The problem is that the majority of trains are bi-directional and a lot longer than a car.

There certainly won’t be an easy fix, maybe air intake under the carriages then it can just ingest the brake dust instead 

[Gwiwer]

2 hours ago, jamie92208 said:

Slightly off topic it's due to the high price of gas and the downside is that the UK is now short of Carbon Dioxide.

 

Jamie

Short of commercial CO2 for food use maybe.  We have more than enough atmospheric CO2 thank you  

 

 

[rodent279]

32 minutes ago, boxbrownie said:

There certainly won’t be an easy fix, maybe air intake under the carriages then it can just ingest the brake dust instead 

Does there need to be a fix, or is this just a non-story produced by a journalist who hasn't presented the facts in full context?

As mentioned above, comparing the peak levels in a train with the average on a road is meaningless without other information, such as number & duration of samples, time of day etc.

[62613]

3 minutes ago, rodent279 said:

As mentioned above, comparing the peak levels in a train with the average on a road is meaningless without other information, such as number & duration of samples, time of day etc.

It almost sounds like your typical anti - rail article. Of which there have been many over the years. If the paper's editor thinks it's a slow news day, they aren't paying attention!