That's wheel howl, and unless the sharp curves are straightened out, making both rails the same length, there's not much that can be done to stop it.
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Comparison of Class 68 noise levels with other locomotives
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And was something that was 'going to be sorted out' after the complaints rolled in when the platforms first opened .......
delticdave
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Slightly going off topic, but about the noise.
Just have a watch and listen of this YouTube video.
I myself have been to Chicago on these Metra trains into Ogilvie Transportation Center, and it is the nosiest train station i have ever been to, anywhere!
All those diesel locomotives are running at high RPMs continually to provide Head End Power (HEP), equivalent to our Electric Train Supply for the coaches.
Maybe this is what stations like Lime Street, Man Victoria and the like have got to look forward to... In a smaller way of coarse!!
Most of Metra's diesels generate the trains HEP from a 3-phase generator, driven by the prime mover, so the engines have to run at 893 rpm to provide the 60 cycle supply. Some of their newer locos have a separate (& quieter) HEP gen-set, so the main engine can be shut-down, or runs at idle speed.
Most USA & Canadian commuter agencies have purchased new locos &/or modified their existing diesels with HEP gen-sets, as have Amtrak & VIA Rail Canada.
Toronto Union & L.A. Union are much quieter places now....
The Deltics had 36 cylinders of 2-stroke and were "high revving" 1500 rpm units, which explains their characteristic "hum" when giving a bit of welly. Must be up there with the louder locos.As an enthusiast, personally speaking, when it comes to wibble I'd put thrash and noise before paint and clag.....but we're all different
But seriously, I agree, a Valenta powered HST is quite possibly the noisiest train I've ever stood next to went it starts up, and in this case it's the screaming sound more than anything else. I noticed recently how much quieter the re-engined ones are (are the LNER ones MTU? I can't remember).
The other thing I've noticed recently from watching a lot of older videos of 80s traction is just how smoky/claggy/dirty (or however you want to describe them) older diesels really were. I don't remember them like that myself at the time but in every video, everything smokes and clags. In comparison a 68 is a breath of (slighty) fresher air.
I do think the 68s are the best sounding modern diesel, and for this enthusiast, sitting in the ironically positioned quiet coach (1st one behind the loco in a Chiltern set) is quite fun. Having said that I imagine that as we have far fewer diesels locos around these days, the minute we get one that has a bit of noise about it (let's face it, 66s aren't anything like as loud), it does rather stand out. Places like Liverpool Lime St mentioned above or Man Vic, and many others are now home to more electric trains than ever before, or somewhat quieter DMUs and haven't seen diesel loco hauled trains in some time. People will have got used to a lot less noise.
Just my opinion anyway....
JohnMcL7
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I was wondering that as well as I was between a 67 on the Inverness sleeper (which seems to sit with the engine on for a good portion of the day) and a 37 also idling, I thought the 37 would be a lot louder but they seemed to be competing quite well with each other.
Old locos such as 37s, the EE engines have a low idle RPM and the exhaust manifold / turbocharger arrangement causes the notable "intermittent blurt". The turbochargers themselves provide a fair level of silencing. The arrangement of a four-stroke turbo-diesel manifold is configured in respect to the firing order so that the pulses from each cylinder don't disturb each other and cause efficiency losses at the turbo turbine. That's just external exhaust noise though, internally all you really hear is a constant rickety ticking from the rocker gear, whining from pump bearings, humming from the generator fan, whirling from turbos and maybe the odd clapping from imperfect exhaust joints or miss-timed injector pumps. Add the resonance of being contained in a steel shell too.
I'd probably rather be in an engine room with an idling EE engine than stood next to a Cummins QSK19...
From what I've picked up, the 68s obviously have the 16 cylinder engine but also two hydrostatic circuits for radiator cooling fans / inverter & motor blowers that cause the constant whining sound. When in motion the resonance of the IGBT / AC traction motor sound becomes noticable. In essence, they have the noisiest aspects of a diesel loco, DMU and EMU in one package.
Also..... Even if a 68 idled the same speed as a 37, it would be firing more frequently - every 90 degree as apposed to 120 degree of the crank respectively. 12 Cylinder EMD engines in 57/66/67 are in a nature of their own in terms of firing order / exhaust scavenging - turbo arrangement hence their unique acoustics.
I'd probably rather be in an engine room with an idling EE engine than stood next to a Cummins QSK19...
From what I've picked up, the 68s obviously have the 16 cylinder engine but also two hydrostatic circuits for radiator cooling fans / inverter & motor blowers that cause the constant whining sound. When in motion the resonance of the IGBT / AC traction motor sound becomes noticable. In essence, they have the noisiest aspects of a diesel loco, DMU and EMU in one package.
Also..... Even if a 68 idled the same speed as a 37, it would be firing more frequently - every 90 degree as apposed to 120 degree of the crank respectively. 12 Cylinder EMD engines in 57/66/67 are in a nature of their own in terms of firing order / exhaust scavenging - turbo arrangement hence their unique acoustics.
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The class 700 screech and howl from what I've witnessed are probably louder than when the class 319s / 377s / 387s used to run this line. Despite the newer trains being built with lower wheelbase bogies.
The noise is pretty much inaudible at the northern end/on the concourse but still averages over 100dB when at the southern end. Surely a candidate for the UKs loudest station for screech and wheel howling.
This video demonstrates it clearly.
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43096
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Try Boston, then, as the HEP gen-sets drown out the EMD 645 noise of the F40s and GP40s.
sjpowermac
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Thank you for that. Now all we need to do is get a Class 68 at that location
delt1c
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Would love to know the figures for Delt1c’s and Westerns. Pure music
Yup I'm sure class 73s have ran through there on engineering trains imagine the level of thrashThank you for that. Now all we need to do is get a Class 68 at that location
sjpowermac
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Thank you so much for that, what an informative post. I’d heard before about the traction motors whining, thank you for confirming. In the clip below, I’d guess the sound is the one that kicks in at about 16 seconds.
Any offers on why there’s an initial take up on power, pause, then further power up and then the train moves? Is that down to driving technique or a feature of the locos?
Thank you again for the information in your post.
sjpowermac
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I’ll certainly have a go at finding out next time I see one
I can only provide an educated guess as I'm not involved with these locos in any way. I have studied them in the past using info I've found online.
The driving controls signal to the VCU (vehicle control unit), the two traction converters have controllers which controls the alternator output, traction motors power and auxiliary power and also the engine via it's ECM (engine control module). Each of these communicate on a CAN-Bus so there will be automated logic in the way that these demands are handled. The engine will probably speed up initially for anti-stall purposes and when loaded (electrical load on the alternator) will dip in RPM, once all is settled the engine speed, alternator output and IGBT frequency will be at the mercy of the driver's request (with the VCU actually doing the calculations).
This is actually similar to a loco from the 60s, except they use old fashioned mechanical and electrical control gear rather than electronic signals!
FFFC 57
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That's what I meant. Just you've explained it much better than I could. My power unit knowledge is limited to English Electric, Sulzer, Paxman and EMD.
FFFC 57
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Spot on it's a manual operation, but look on the cab end of the DT and the sticker warns the loco must be disconnected before the shore supply is fitted. This would add a lot of time to the procedure.
delticdave
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It's been a while since I've visited Boston. but ISTR that the locomotives were at the outer end of the commuter consists at both South & North stations. Amtrak loco-hauled e-loks at South station could be noisy but zero emissions, but the Downeasters from North station used cabbages & GE P40's, & the loco's might have been on either end.
richa2002
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The initial rev up is the reverser being placed into forward.
43096
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Yes, the locos are country end at both Boston stations for MBTA services. The Amtrak electrics (all Siemens ACS-64s now) weren’t at all intrusive, though the Acela power cars were a bit noisier. When I was there in August the Downeaster sets all had the cabbages at the Boston end and a P42 country end.
ac6000cw
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Yes, they are (with both engines running) - no turbochargers to deaden the exhaust noise either... After they went into service, they had to add extra sound insulation in the cabs due to complaints from the crews about high levels of engine noise.
The old Irish Rail 141/181 locos were pretty raucous too - an EMD 645 V8 Roots-blown 2-stroke with (if they are like contemporary US locos) minimal exhaust plumbing between engine and roof outlet.
Just to add my twopennorth, when sat in Rail House at Lime St on the 6th floor, you can certainly now tell there’s a 68 in the station, and walking through the station they certainly make their presence felt. However I think a potential fly in the ointment could be if any of the nearby hotels, and the student accommodations being finished off could bring noise complaints in against the station. (We can have the arguementd about rail being there first, I agree, but the law doesn’t). Would it be possible to implement some kind of stop/start technology on the loco, or would it need a ridiculous number of batteries? With 221s. We have to do an engine shutdown if sat for over 20m anywhere, the batteries can cope with this and with them also being 5 car, should imagine hotel power is a similar amount of draw on the batteries.
Regarding Deltics, the main 'humming/droning' sound when idling is the air reverberating in the engine air intakes on the side above the nameplates, that's why you can feel the air in your lungs vibrating when stood there. It's also why they sound different under an overall roof as the two intakes either side harmonise together. The other principle sound at idle is the phasing gears. Only when really opened up can you hear the exhaust note.
DelW
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IIRC there was a thread on here some years ago, started and maintained by a resident of a flat near Marylebone station, who was trying to get some sort of injunction on Chiltern to shut down the 68's in the station, since he reckoned they were so much noisier than their predecessors.
Around the same time there was discussion of a plan to add generator sets to the DVTs, though I'm not sure whether that was to maintain train power while allowing the loco to be shut down, or for some other purpose. I think a test installation was done, but I've not heard of it since, so maybe it wasn't successful enough to roll out further (unless anyone knows differently of course).
sprinterguy
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The Chiltern DVTs were all fitted with generators during 2012, specifically to provide power to the train when the loco is shut down. I believe this is how power is provided to the mark 3 sets while they're stabled at Marylebone these days.
The Chiltern DVTs are fitted with 250kW Volvo Penta generators to power their six carriage mark 3 sets. Not sure what the power draw of a mark 5 carriage is by comparison, but I wouldn't have thought it was that much higher?
Alanko
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Interesting thread. My 385 came into platform 12 of Waverley last week, and I could tell that there as a Fife Circle 68 over the other side of Waverley even before I stepped off the train. It isn't loud perhaps, but the sound is somewhat unique and seems to cut through other noise. Presumably it is rich in the sort of frequencies and harmonic content that are absent in the 'note' of other trains? I like the sound but it is hard to miss; somewhat like having a chinook flying around.
FrodshamJnct
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Totally agree with that description. Just walked into Lime Street and thought ‘what is that?’ It was the TPE set about to depart on the 1356. It sounded great!
Thanks - how big is one of those? Unfeasible to fit anywhere on a TPE set without a new carriage?
the "baby" deltics were turbocharged but weren't too successful I've often wondered what we'd have had if EMD's pressure charging arrangement of a supercharger and turbocharger had been available back then. That's the arrangement where the turbo takes over from and declutches the supercharger at higher revs and engine loads, allowing more power to be available at the output shaft. At least 2000bhp per engine? And quieter exhaust too.
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