Great Western Coffee Shop

Just a Question, I'd love SOMEONE to defend FGW on this one.

It's claimed that the Re-engined HST's (fitted with MTU power units) are much much cleaner than the Older engines that have been replaced, indeed when Idleing I understsnd that the MTU go over to ONE Bank firing.

So why ARE FGW HST's still left outside the Train shed at Penzance?

FGW need permission from RSSB or someother body to send HST's to the blocks at PNZ?.

After all, all other trains go right up to the Blocks at PNZ.

I expect the answer is FGW HAVEN'T done there Homework and ASKED.

I'm no expert on the layout at Penzance, but what is signal sighting like there? Trains need to be at certain points so driver has a clear view of the either signal or a banner repeater. (This is a similar issue at Paddington - HST's on Platform 8 for example don't come right to the blocks)

Could be because of the noise of which the power cars make, MTUs idle much louder than the Paxman Valenta engine. My understanding is that people from the hotels above were complaining.

It's not a Signal sighting Issue, and as for noise, can't see Noise being an issue as the High Wall above Platform One deflects Noise away from the Hotels on the Road above.

Note: When HST's use Platform Three they do work right up to the blocks.

i hesitate to say this as it.... well its me thinking it .... but do hst's not fuel up at long rock?

I don't think there's any doubt at all that they are hugely cleaner...I well remember the smoke screens that the Valenta-powered HSTs could create when they pulled out of Temple Meads heading towards London after idling for a while in the platform.

I don't know PNZ station at all - how long is the trainshed? Is it possible that a single 2250 hp engine is still considered too large to have idling under the roof, whereas a few (much smaller) DMU engines aren't considered a problem?


Really...? I have no idea of the numbers, but I'd be amazed if that was actually true - the MTUs have always sounded somewhat quieter at idle than the Valentas to me. The first time I caught an HST that had a re-engined powercar on the front it seemed so quiet as it coasted into the station I thought the engine in it was shut down for a moment or two until the penny dropped.

From a person who spends his working day sat in front of one of these engines I can confidently say NO WAY

Fair enough, would you say it could be something to do with the fact they seem to idle at a lower pitch compared to Valentas?

Probably you tend to feel rather than hear an MTU when in the Manor and one stops on Platform 2 at Slough.

MTUs are far better sound proofed, particularly in the cab. I understand that originally there was too much soundproofing and drivers were complaining that they couldn't hear the engine!

Nothing has been done on the soundproofing of the cab.

except

The fitting of new outer cab doors and door seals in an attempt to eliminate wind noise.

The engines are quieter end of!

There are a number of instructions relating to Penzance Station and the positioning of HSTs there , these are contained in The Network Rail Western Region Sectional Appendix and are quite detailed and appear to be in place with regards to noise abatement

The roof cladding at Penzance was replaced some time ago, around 1991 I think. For a few years the roof cladding was missing with only the framework remaining in place. When Regional Railways replaced the roof the vents in the top of it were made somewhat smaller than before. Therefore the fumes from loco's / Valenta engined HST's couldn't escape through the vents as readily as before. The current instructions were based on this and haven't been updated as a result of MTU engines although simply because there less visible clag that doesn't mean that there aren't nasties in the air that need to be dissipated.

The requirement to leave Penzance in notch one, take notch two somewhere around Slopers and then notch up normally approching Long Rock has been removed from the instructions though.

And yet XC HST's are worked to the blocks at Penzance, well the last one I saw at Penzance was at the blocks.

I'll agree with dog box about Penzance station Roof but when it was rebuilt (1991 would be about right) some IDIOT sealed one side of the roof vortex the WHOLE length of the roof, hence there is NO Vortex, a very simple and easy way to ensure Natural ventilation.

The Vortex works thus: Air Passing over the Roof is at a lower pressure than air within the train shed so having BOTH sides of the High level top box OPEN causes the Air passing through to act as a Vacuum cleaner, keeping the train shed ventilated.

Sealed one side NO VORTEX:

Just another point, the MTU engines actually go into a 'split bank' mode when idling or on Train Supply, where by two halves of each bank ie. 6 and 6 fire only and it changes over every 10mins or so, making a sound like the engine 'coughs' briefly!

Say If MTU engine's are quiet, what the Heck is the Problem with 43026?

I reckon when I heard it earlier today (Stationary), that it would given a Class 55 Deltic a run for it's money (Noise level wise).

That will be the fairly substantial Electric Cooling Fans Running

Another power car 43069 had been running around sounding the same on another set which kept shuddering and shaking as it pulled away from a stop.I assumed both power cars 43026/43069 have the same fault.Any one know what the problem is there.

Cooling fans are blocked. The issue on 069 is known I believe, and the fan has simply been set to stay on full to prevent overheating.

Almost right, the fans are not 'blocked', the radiators in the cooler group that the fan draws air through is blocked/restricted giving restricted airflow and thus degraded cooling ability causing HWTs (High Water Temperatures). As a temporary measure to the problem, the fan controller is being overridden meaning that instead of running at a variable speed depending on the temperature, the fan runs at full speed constantly.

The fan by the way, is hydraulically powered from a shaft off of the 'free' end of the engine with its operation being via an electronic controller that interfaces with the MTU engine 'MDEC' ECU.

The power cars will be stopped for repair, which will consist of either steam cleaning of the radiator panels, or a change of cooler group, which will then hopefully put a stop to the HWT issues it is having!

Correct or near enough. At the time under OFQ the BR buisness sectors 'owned' the bits of track, stations and signalling that they ran over or were deemed the predominant operator of. Plymouth - Penzance was deemed to be a Regional Railways route. As such when the roof was replaced at Penzance, Regional Railways underwrote the cost of reinstating the roof on the extant framework. As Intercity were reluctant to fork out money for the project the roof vents were reassembled / replaced on the basis of small 14 litre Cummins engines standing underneath the roof. The smaller openings reduced the possibilities of sea spray corroding the existing steelwork in the roof. Intercity by then being mainly Sulzer 12LDA28C or Valenta 12RP200L powered. Intercity being happy for their trains to come to rest outside the train shed. This still applies today and this includes XC services using HST's notwithstanding the replacement of all the Valenta engines with the MTU engines.

The long standing instruction regarding notching up HST's to N1 only when leaving Penzance, N2 at Slopers and N3 upwards at Long Rock have however dissapeared from the book of words and the lineside signs have been removed.

However its worth bearing all this sort of thing in mind when considering / talking up Vertical integration of track and services by operator, particularly when more than one operator may be involved. Some of us have seen this all before......

43069 is I believe in LA currently for a cooler group change, the fan controls having been set for the fan to run at all times when the engine is running prior to this cooler group change. I seem to remember N5 being strapped out on this power car due to HWT issues., Hopefully it should be nice and quiet when it comes back.

Still in service Tuesday making a terrible din passing through Newton Abbot....

The country end power car does sit under the train-shed at PNZ on Platform 1.