Train Cancelled Due To High Pollen Count

[Llandudno]

Travelled on Northern’s 1117 service from Nottingham to Leeds yesterday on one of the 2 car CAF units.

On arrival at Dronfield the trains engines cut out and the driver was unable to restart the unit blocking the main line between Chesterfield and Sheffield.

The guard was extremely informative advising passengers that the driver was on the phone to the depot seeking assistance. Eventually after around 20 minutes the driver managed to restart the train and we limped into Sheffield were the train was terminated short and the 50+ passengers wanting to go Leeds were advised to catch the XC train behind, thankfully we were allowed to board the XC voyager despite not having reservations!

The cheery Northern guard had great delight informing passengers that a High Pollen Count affecting the engines coolant level was the reason for the engines cutting out, he was non too complimentary about the Spanish trains in general.

Is this a common fault with the CAF units, it was a hot day, yesterday, not excessively so, around 26C, I am pretty certain it gets hotter than that in Spain were the trains were manufactured!

 

[jonnyfan]

Last year we had a spate of engines on the 195s overheating in early summer, and it was found to be down to pollen blocking the engine ventilation systems - they did get on top of it and the problem has been far less of an issue this year, only heard of a couple of instances.

 

[hwl]

Travelled on Northern’s 1117 service from Nottingham to Leeds yesterday on one of the 2 car CAF units.

On arrival at Dronfield the trains engines cut out and the driver was unable to restart the unit blocking the main line between Chesterfield and Sheffield.

The guard was extremely informative advising passengers that the driver was on the phone to the depot seeking assistance. Eventually after around 20 minutes the driver managed to restart the train and we limped into Sheffield were the train was terminated short and the 50+ passengers wanting to go Leeds were advised to catch the XC train behind, thankfully we were allowed to board the XC voyager despite not having reservations!

The cheery Northern guard had great delight informing passengers that a High Pollen Count affecting the engines coolant level was the reason for the engines cutting out, he was non too complimentary about the Spanish trains in general.

Is this a common fault with the CAF units, it was a hot day, yesterday, not excessively so, around 26C, I am pretty certain it gets hotter than that in Spain were the trains were manufactured!

Engine and cooler groups etc supplied by a German subsidiary of Rolls Royce with the engines being rebadged Mercedes HGV engines

 

[Dr_Paul]

The cheery Northern guard had great delight informing passengers that a High Pollen Count affecting the engines coolant level was the reason for the engines cutting out...

I wonder what the passengers' responses were to that!

 

[Statto]

I wonder what the passengers' responses were to that!

Most likely sniffed at it.

 

[Paul Jones 88]

Surprised it didn't make the news like the 1991 Wrong Type of Snow.

 

[Llandudno]

I wonder what the passengers' responses were to that!

Incredulity!

or more likely WTF…!

 

[A0]

Last year we had a spate of engines on the 195s overheating in early summer, and it was found to be down to pollen blocking the engine ventilation systems - they did get on top of it and the problem has been far less of an issue this year, only heard of a couple of instances.

IIRC, it was the same issue on the 230s on the Marston Vale line - which runs alongside many fields etc. Blocked filters causing engines to overheat.

As an aside, I don't think it's just pollen - when pollen counts are high there tend to be other airborne particles blowing around - dust etc. Usually a result of a longish dry spell, whereas when there's been some rain it dampens all these particles down and they are no longer airborne - and therefore less likely to be ingested in the air intake of engines.

 

[yorksrob]

I did have quite bad hayfever yesterday, so can attest.

They used to pillory our old electric trains when powdery snow affected the traction engines.

 

[rustbucket]

Last year we had a spate of engines on the 195s overheating in early summer, and it was found to be down to pollen blocking the engine ventilation systems - they did get on top of it and the problem has been far less of an issue this year, only heard of a couple of instances.

One of the many popular reasons for 180s to fail as well. At one point I am sure Old Oak were having to power wash the filters every night

 

[driverd]

Most likely sniffed at it.

Or perhaps sneezed!

It does boggle the mind that even with a 2015(ish) designed train we can't get on top of a problem that has affected every single DMU fleet since the 14x's (and probably even before then).

 

[Wilts Wanderer]

Didn’t the early delivered 800/5 sets with GWR suffer similar issues (multiple engine failures) in their first summer in traffic? I seem to recall a robust filter cleaning process was introduced and it seemingly hasn’t recurred.

 

[fgwrich]

One of the many popular reasons for 180s to fail as well. At one point I am sure Old Oak were having to power wash the filters every night

Indeed. Although unfortunately the stupidity / fragility of the design meant it wasn't difficult for the 180s to fail. I'm sure the Hull / GC units were the most affected.

 

[IanXC]

I'm sure the Hull / GC units were the most affected.

So, all of them then?

 

[wobman]

IIRC, it was the same issue on the 230s on the Marston Vale line - which runs alongside many fields etc. Blocked filters causing engines to overheat.

As an aside, I don't think it's just pollen - when pollen counts are high there tend to be other airborne particles blowing around - dust etc. Usually a result of a longish dry spell, whereas when there's been some rain it dampens all these particles down and they are no longer airborne - and therefore less likely to be ingested in the air intake of engines.

The TFW 230's are having the same overheating problems, the 175's have a filter that can be removed that the pollen and rubbish stick to Infront of the radiator. It's a common problem in the summer with most units unfortunately, as network rail don't cut back foliage nowadays.

 

[Roast Veg]

Or perhaps sneezed!

It does boggle the mind that even with a 2015(ish) designed train we can't get on top of a problem that has affected every single DMU fleet since the 14x's (and probably even before then).

I think that rather gives credence to why it might be a rather difficult issue to get on top of.

 

[driverd]

I think that rather gives credence to why it might be a rather difficult issue to get on top of.

Point well made!

None the less, it does puzzle me a little as we don't face a similar issue with road vehicles. You would have thought that, with the amount of money spent on R&D for this type of application, a solution would have been found.

 

[Spartacus]

Point well made!

None the less, it does puzzle me a little as we don't face a similar issue with road vehicles. You would have thought that, with the amount of money spent on R&D for this type of application, a solution would have been found.

Possibly a location issue, the airflow onto the front of a road vehicle might stop the particles building up, whereas you can't generally put it there on a rail vehicle. I wonder if it's also a problem on rear engined buses, I know in hot weather it was always hardly uncommon to see them with the compartment door open, sometimes even while travelling!

 

[squizzler]

Most likely sniffed at it.

They enjoyed their ride on an Ah-choo! Ah-Choo! train.

 

[fgwrich]

So, all of them then?

No, because GW were operating their 5 at the same time. For some reason I don't recall hearing as many failures of the GW fleet (particularly as OOC knew them well) compared to the Crofton maintained GC & Hull units (though OOC did the heavy stuff on the HT units in the end).

 

[DarloRich]

We had similar issues down here with the 230's.

 

[A0]

The TFW 230's are having the same overheating problems, the 175's have a filter that can be removed that the pollen and rubbish stick to Infront of the radiator. It's a common problem in the summer with most units unfortunately, as network rail don't cut back foliage nowadays.

Not cutting back vegetation is largely irrelevant. Pollen particles are small and easily blown by the wind. Even if you had bare concrete on the cuttings etc, you'd still have a pollen problem because it would simply be blown from the surrounding trees and fields. And the problem isn't confined to pollen, there are other particles which are distributed in this way. The only thing which helps is having regular rainfall - not a couple of short sharp showers - which basically washes such particles out of the air. It's why hayfever sufferers (such as myself) welcome a couple of days steady rain as it drops the pollen count noticeably and gives us some respite.

== Doublepost prevention - post automatically merged: 18 Jun 2021 ==

We had similar issues down here with the 230's.

As I said in post #8.

== Doublepost prevention - post automatically merged: 18 Jun 2021 ==

Point well made!

None the less, it does puzzle me a little as we don't face a similar issue with road vehicles. You would have thought that, with the amount of money spent on R&D for this type of application, a solution would have been found.

Well with cars you have the air intake more concealed - it's under the bonnet and is sucking up air from below the engine bay or that has come through the radiator grilles (if the car has them). The problem with trains is they are not so boxed in - which is largely due to the design - but also the need to 'suck in' far more air than a relatively small car engine.

A car, when serviced, should have its air filter replaced and most modern cars have a pollen filter which is part of the cabin cooling / heating system. Blocked pollen filters in cars do cause problems, but not usually overheating - more commonly it causes problem with airflow into the cabin and can lead to water ingress into the cabin.

== Doublepost prevention - post automatically merged: 18 Jun 2021 ==

Possibly a location issue, the airflow onto the front of a road vehicle might stop the particles building up, whereas you can't generally put it there on a rail vehicle. I wonder if it's also a problem on rear engined buses, I know in hot weather it was always hardly uncommon to see them with the compartment door open, sometimes even while travelling!

Spot on - it's the location and also the volume of air sucked in.

Not sure you're right about rear-engined buses running with compartment doors open - usually these are controlled by microswitches which kill the engine if these are open because you don't want them flying open at speed which could be dangerous.

The Mk1 Leyland National was known for running hot - it was part of the reason why the National 2 and Lynx switched to having a front radiator - though that can create a different problem in that you end up with miles of pipework running from front to back which can easily lead to air pockets or air bubbles in the cooling systems. Water cooled rear engine cars tend to have similar problems.

 

[ainsworth74]

None the less, it does puzzle me a little as we don't face a similar issue with road vehicles. You would have thought that, with the amount of money spent on R&D for this type of application, a solution would have been found.

Well, for one, the engines on road vehicles tend to be smaller and less powerful (less heat). Taking the most popular cars at the moment (by registration) such as the Vauxhall Corsa and Ford Fiesta you're looking at between 70 and 140 horsepower (there is a very sporty model of Fiesta that 197 but I think it's safe to assume most Fiesta are using more stock engines!). Even for something a bit bigger like a Mercedes-Benz A Class or Nissan Qashqai you're talking between 100 and 300 horsepower (with some of the premium engine configurations on the Mercedes getting up to 400).

Meanwhile the 195 has over 500 horsepower whilst the 80xs and 180s are pushing 750 horsepower (though they may be de-rated below level usually). These are big powerful (hot) engines. We're then cramming them into a space which is basically a tiny box under the floor where there is some natural ventilation and trying to cram in radiators and all the associated cooling systems around them. Which means you're need your radiators operating at peak efficiency to make sure they're getting the maximum amount of cooling possible. Meanwhile our car whilst it is also cramming the engine into a small space has the advantage of sticking the radiator right up front with a nice gaping hole meaning that as you go faster more and more air can be rammed through it helping to bleed off more and more heat even as the engine is working harder.

To be honest I think it's a minor miracle that these modern diesel engines are able to be cooled at all outside of cold days!

 

[A0]

Well, for one, the engines on road vehicles tend to be smaller and less powerful (less heat). Taking the most popular cars at the moment (by registration) such as the Vauxhall Corsa and Ford Fiesta you're looking at between 70 and 140 horsepower (there is a very sporty model of Fiesta that 197 but I think it's safe to assume most Fiesta are using more stock engines!). Even for something a bit bigger like a Mercedes-Benz A Class or Nissan Qashqai you're talking between 100 and 300 horsepower (with some of the premium engine configurations on the Mercedes getting up to 400).

Meanwhile the 195 has over 500 horsepower whilst the 80xs and 180s are pushing 750 horsepower (though they may be de-rated below level usually). These are big powerful (hot) engines. We're then cramming them into a space which is basically a tiny box under the floor where there is some natural ventilation and trying to cram in radiators and all the associated cooling systems around them. Which means you're need your radiators operating at peak efficiency to make sure they're getting the maximum amount of cooling possible. Meanwhile our car whilst it is also cramming the engine into a small space has the advantage of sticking the radiator right up front with a nice gaping hole meaning that as you go faster more and more air can be rammed through it helping to bleed off more and more heat even as the engine is working harder.

To be honest I think it's a minor miracle that these modern diesel engines are able to be cooled at all outside of cold days!

The power (HP) of the engine isn't really the issue - it's the cubic capacity of the engine really as it's the mixture of fuel and air which drives the cylinders (either as ignition in petrol or compression in diesel). In a road car engine you're looking at that capacity being 1.0-1.5 litre - whereas with a 195 you're looking at a 13 litre engine - so the amount of air required as part of the compression (as it's a diesel engine) will be far greater.

In your comment about the sporty small cars - they tend to use the same basic engine, but various things are done to it in order to increase that power output - most commonly nowadays are turbo-chargers. Mainly because we've gone down the route of turbo-charging very small engines to within an inch of their life - and then wonder why they go bang, usually in a fairly spectacular way, by about 100,000 miles......... Slightly larger, less stressed engines tend to cope with high mileages much better - as the Americans and Japanese know which is why many of their cars have, by European standards, relatively large capacity engines with lowish power outputs.

 

[ac6000cw]

I think the basic problem is that with the limited space available under the carriage, as engine power outputs have increased (e.g. almost doubled from a 150 to a 195) it's forced the use of high-efficiency radiators with relatively fine pitch fins combined with high flow rate fans. This is almost bound to increase the rate of clogging up air passages through the radiator fins with debris, dust and pollen over time - compounded by DMU radiators being close to the ground where dust/debris gets stirred up by the airflow around the train.

 

[37057]

I once saw that Northern modified a DMU a while ago so the cooling fan could be reversed to blow out debris from the radiator, not sure how effective it was though.

 

[Spartacus]

Spot on - it's the location and also the volume of air sucked in.

Not sure you're right about rear-engined buses running with compartment doors open - usually these are controlled by microswitches which kill the engine if these are open because you don't want them flying open at speed which could be dangerous.

It's not as common as it once was, but I remember a coach travelling on the M62 one summer's evening with his open, no doubt with a strategically placed glasses arm or similar somewhere to fool the switch. I fount it was remarkably easily done a few years ago when our broken down coach rolled back into the one we were in the process of switching to, destroying the front of the new coach, but doing no damage at all to the failed coach other than neatly snapping off the engine door. Front coach fault was easier to repair than the coachwork & windows on the rear one, so that was done and we carried sans engine door.

 

[VT_Valenta]

I've got nine years experience with running valenta engines (albeit in a maritime application) and our air intakes are continually blocking with pollen, sand, rubbish and general natural detritus. You know when the air intake filters need changing as the engine scream is a lot louder at lower powers. In one instance, power was down by about 300-400 kw because the filter was chock-full of sand.

 

[cnjb8]

No wonder it’s an issue on that particular route. I took the train from Nottingham to Alfreton last week and the trees were brushing up against the train. It was a 195 as well!

 

[coppercapped]

The power (HP) of the engine isn't really the issue - it's the cubic capacity of the engine really as it's the mixture of fuel and air which drives the cylinders (either as ignition in petrol or compression in diesel). In a road car engine you're looking at that capacity being 1.0-1.5 litre - whereas with a 195 you're looking at a 13 litre engine - so the amount of air required as part of the compression (as it's a diesel engine) will be far greater.

In your comment about the sporty small cars - they tend to use the same basic engine, but various things are done to it in order to increase that power output - most commonly nowadays are turbo-chargers. Mainly because we've gone down the route of turbo-charging very small engines to within an inch of their life - and then wonder why they go bang, usually in a fairly spectacular way, by about 100,000 miles......... Slightly larger, less stressed engines tend to cope with high mileages much better - as the Americans and Japanese know which is why many of their cars have, by European standards, relatively large capacity engines with lowish power outputs.

I beg to differ - it is largely about engine power.

A diesel engine is around 30-40% efficient - depending on load and engine speed - at turning the chemical energy in the fuel to useful work in moving the train. Ignoring the heat lost through the exhaust gases this means that some 60-70% of the energy in the fuel has to be dumped by the cooling system. So a 500bhp engine has to dump over 1000hp worth of heat through the radiators.

Because of the limited space available for underfloor engines the radiators are constrained in size - which means that in order to dump these quantities of heat on a hot day the cooling system has to work very effectively. Any reduction in the ability of the cooler group to dump the heat will be noticeable.

Unlike road vehicles there is no ram effect in trains where the vehicle's forward motion forces air through the radiator. In road vehicles the fan is often only needed when the vehicle is stationary or slow moving whereas the only way that air is drawn through the radiator matrix in a rail vehicle is by a fan.

Cars only use much or all of their maximum engine power when accelerating - and this only last a few seconds (0 to 60mph in 10 seconds or less...). At constant speed the engine power needed is in the order of a few tens of horsepower so the quantity of unuseable heat which needs to be dumped is comparatively small - in the order of 100hp or so. Lorries are slightly different in that high or maximum engine power is needed for longer periods or when climbing long inclines - these are more akin to rail vehicles and the radiators are sized to cope.

I am not surprised that difficulties arise in the cooling of underfloor engines in hot, dusty weather.