Why are HST's (Class 43's) so loud?

[londonmidland]

Does the NMT still have Valenta engines?

No, the NMT Trains have MTU's.

 

[ChrisCooper]

VP185s have a louder and higher pitched squeel when on full power due to having smaller but faster revolving turbochargers. They lack the same deep rumble of the Valentas though, infact they have a very tractory sound to them. I think they are quieter on idle, but noisier on full power, but that might just be hearing sensitivity (high pitch sounds tend to sound louder than lower pitch ones). Would be interesting to know what the noise level is standing next to Valenta HST providing ETS and a QSK19 equiped DMU on idle. I bet there is not much in it. The difference is that it's one coach of the HST making that noise (even the other end is either quieter or even silent if shut down at a teminus), compared to every coach on a DMU.

Actually, I wonder what DB wise the loudest trains in the UK are? Deltics probably. Valenta HSTs would be up there, but what else? Would be interesting to use a sound meter on some. For fairness it would have to be from the same location, not from the adjacent platform (as that would give DMUs an unfair advantage) and if it was engine noise, line speed would have to be fairly low or else aerodynamic noise would play a part, yet ideally all trains would be full power. Lineside on the exit to a station would probably be best, or just go for stationary and idling at a station.

 

[brillopad]

I used to work a mile away from St Erth Station and kept the window open to hear the Valentas throttling down as they approached the station - the turbo whine and fan noise was mesmerising.


Valenta on youtube

another

another starting


Valenta clag

Clag & turbo whine

 

[4SRKT]

I'm genuinely confused by the OP here. HST power cars loud? They are exceptionally quiet for a diesel engine. I remember reading a Q&A on the internet about the MTU re-engining programme which stated various reasons for the change from Valentas, one of which was that MTUs were quieter and made less exhaust when under load than an Valenta did while idling. Never mind Valentas, loud though they are. What would the OP make of a world where pairs of 37s on freights (or on holiday trains to Aberystwyth - bliss) were commonplace. I can't imagine there has ever been a louder railway related noise in this country than a 37 starting a heavy train, with the possible exception of a 56 doing the same.

 

[sprinterguy]

Never mind Valentas, loud though they are. What would the OP make of a world where pairs of 37s on freights (or on holiday trains to Aberystwyth - bliss) were commonplace. I can't imagine there has ever been a louder railway related noise in this country than a 37 starting a heavy train, with the possible exception of a 56 doing the same.

I was just thinking the other day while watching the Seaton-on-Tees nuclear flasks go by that the railways are a much quieter place today in terms of engine noise than they once were. Even on such a lightweight load as a pair of flasks a 37+20 pairing still makes one hell of an impressive racket, though IMO there's very little that tops the sound of a 56 accelerating hard at the head of a loaded rake of HAAs. That was quite something to behold.

The Valentas made an absolutely fantastic noise, and the MTUs are much quieter in comparison. I've always found the engines under a Voyager to be extremely loud when stood alongside one at a station, given that their 750hp power units are only a third of the size of the engine in an HST Power car.

Apparently, at the design stage for the HSTs there was an option for fitting an uprated 3,000hp power unit, that would have fit within the power car bodyshell, to the East Coast class 254 trains to cope with the additional carriage these sets had, but the idea was dropped: Can you imagine how much noise one of those would have made compared to the existing 2,250hp engines??

 

[The Crab]

Years ago I was in a meeting on about the 8th floor of an office block near Sheffield station. Suddenly there was such a noise from the station that everyone went to the window to see what was making such a racket. It was a pair of 37s on a heavy steel train heading south & talk about clag!!

 

[Peter Mugridge]

For real high volume low pitch pounding noise, nothing will ever beat standing at the fence at Blackwell Court in the days of 45s and 46s on the XC services as they crawled their way up the Lickey with a long rake on...

 

[Irishman]

If a HST leaves the station, you will know about it......

 

[Barrett M95]

Actually, I wonder what DB wise the loudest trains in the UK are? Deltics probably. Valenta HSTs would be up there, but what else? Would be interesting to use a sound meter on some. For fairness it would have to be from the same location, not from the adjacent platform (as that would give DMUs an unfair advantage) and if it was engine noise, line speed would have to be fairly low or else aerodynamic noise would play a part, yet ideally all trains would be full power. Lineside on the exit to a station would probably be best, or just go for stationary and idling at a station.

It's not UK, but TGV transformer fans and pumps, and the motor blowers are very loud in a station (bordering on the volume of a loaded diesel engine I would say, but a very different tone) - what it would register as on a dB meter, I can't say. However at LGV speeds, even that fan noise is completely drowned out by the rail/wheel and aero noise which becomes the dominant factor at 200 to 300km/h.

 

[LE Greys]

It's not UK, but TGV transformer fans and pumps, and the motor blowers are very loud in a station (bordering on the volume of a loaded diesel engine I would say, but a very different tone) - what it would register as on a dB meter, I can't say. However at LGV speeds, even that fan noise is completely drowned out by the rail/wheel and aero noise which becomes the dominant factor at 200 to 300km/h.

Well, that's not so bad, but the brakes go right through you! Same with the Voyager brakes, in fact. With 91s, it's mostly fan noise from the traction motor blowers (which are nowhere near as loud as I've heard from 86s). With HSTs, I'm beginning to like the deeper sound of a V16, but it does sound awfully like a lorry. VPs are a bit more like it, but that's a Valenta with a frog in its throat.

Loudest thing I've ever heard on a railway was actually a King's safety valves lifting. Strange, but true.

 

[ChrisCooper]

It's not UK, but TGV transformer fans and pumps, and the motor blowers are very loud in a station (bordering on the volume of a loaded diesel engine I would say, but a very different tone) - what it would register as on a dB meter, I can't say. However at LGV speeds, even that fan noise is completely drowned out by the rail/wheel and aero noise which becomes the dominant factor at 200 to 300km/h.

Yes, the TGVs and Eurostars are pretty noisy, as are the 91s. Even the hiss of the loco brakes releasing on a 91 is loud. The old DC traction motors on older locos and units can be pretty loud at speed too. Then you get the often quite piercing high pitched squeek of the electronics on modern AC stock, and it's hard to say that electrics really are quiet.

Of cource they might be fairly small in comparison, but a Sprinter or Pacer can make quite a noise when pulling away, especially if the silencer isn't doing it's job very well.

 

[DarloRich]

I'm genuinely confused by the OP here. HST power cars loud? They are exceptionally quiet for a diesel engine. I remember reading a Q&A on the internet about the MTU re-engining programme which stated various reasons for the change from Valentas, one of which was that MTUs were quieter and made less exhaust when under load than an Valenta did while idling. Never mind Valentas, loud though they are. What would the OP make of a world where pairs of 37s on freights (or on holiday trains to Aberystwyth - bliss) were commonplace. I can't imagine there has ever been a louder railway related noise in this country than a 37 starting a heavy train, with the possible exception of a 56 doing the same.

I dont know, a Deltic with a full train from a standing start on a wet rail is canny loud to!

 

[Hydro]

I used to call HST's "Heart attack trains" when I was a nipper because that's what they gave you when opening up under the canopy at Waverley.

My noise fix now comes from 37's. Never liked Deltics, they sound like God's lawnmower.