Does a class 47 sound similar to a class 45/46?

[dimonic]

I know they share a similar engine (the Sulzer 12LDA28 family), and within the limitations of DCC sound and tiny speakers, would it be reasonable to use the Brush 4 sound effects for the Peak? I imagine the horns would be quite different.

[rogerzilla]

Not in my experience.  The 45 is a lot louder and rougher.

[rodent279]

I think the engine in a 47 revs a bit higher-850rpm I believe, that's how the greater power was produced.

[jjb1970]

The noise of an engine tends to be determined by the induction and exhaust arrangements. Identical engines with different induction and exhaust arrangements will sound different.

 

That said, if you don't know what the real machine sounds like, does it really matter?

[Trainshed Terry]

4 hours ago, rodent279 said:

I think the engine in a 47 revs a bit higher-850rpm I believe, that's how the greater power was produced.

 

I do belive that the engine only had an engine speed of a maxium 750rmp. Also the emgines where down rated to 2530HP due stress fractures within the engines when they where first introduced into service.

 

Terry.  

[Halvarras]

My recollection from the increasingly distant past was that the Peak had an additional constant whirring sound, which may have been the traction motor blowers? (The last time I heard a Peak running was immaculate 45149 at the Glos-Warks Rly, 26/7/14, and it sounded much the same as I remember.)

[pheaton]

47s have a c series engine and larger intercoolers

45s and 46s have a b series engine and smaller intercoolers

44s have a b series engine with no intercoolers

 

45/1s have an idle speed of 325 RPM this was added to avoid overloading the engine at idle with the ETH ON

45/0s 44s and 46s and no heat 47s and 47/4s have an idle speed of 250 RPM

 

ETH alternator fitted (not 47/4s) 47s have an idle speed of 325 RPM this was added to avoid overloading the engine at idle with the ETH ON

 

ALL 12 cylinder LDAs max out at 750RPM 47s were derated by an alteration to the governor they did not have a higher RPM

 

The sulzer engine in a 47 is in all intents and purposes for sound exactly the same as a 45...it will make same sounds...however...some 45s have no baffles in the silencer hence will sound louder than a 47....ETH 45s will sound different to NON eth 45s and 47s at idle.

 

45s and 47s load up differently due to the different electrical equipment,  so will sound differently pulling away 45 44s and 46s also have an open bodyshell so will sound different at idle to a 47.

 

the noise halvarras is reffering to is the nose compressor which is very loud in 45149 because its basically in a tin box with lots of openings..

 

a recording of a 45 could easily be distinguished from a recording of a 47... so in my opinion no..they dont sound the same...

 

a 46 has the same electrical equipment (virtually) as a 47...they would sound more similar but.....again because of the open bodyshell they would be a bit louder...and the noise of the auxilliary machines and brake equipment like a 45 and 44 could be heard as well.

Edited March 3, 2023 by pheaton

[Simon Lee]

Class 45 

 

 

Class 47

 

 

 

[w124bob]

Another thing to remember is the cl45/46 only had one exhauster which would have had to work harder(in Vac)thus adding to the general background racket. 

[45125]

A Peak is generally louder on idle due to the open nature of the body work. Ones that have triangular grill are slightly quieter due to all the grills having air filters behind them ( or should have). a Crompton will sound very different to it later 46 sister due to the way the electrical system loads up and the field diverts are totally different the 45 having 5 plus a divert on the main generator were as the 46 has 3 like a 47 (EG 47/7s not included). Like their larger C model cousins they also had the rephrasing done to the crankshafts which also altered the sound.  

 

The raising of the idle revs on ETH fitted locos was to raise the ETH voltage to a more suitable voltage. The voltage was only around 700v untill the idling revs were increased.

 

Al Taylor.

[woodenhead]

But once you older and deafer, they all sound the same, especially if your speakers are cheap.

[keefer]

They might not sound exactly the same but all Sulzer locos sounds similar, inc. the smaller engined cl.24-27 (6-cyl) and 33 (8-cyl).

Similarly, the EE locos sound similar to each other - cl.20, 31, 37, 40 & 50 (though 20s  & 40s have a noticeable 'tweet' or whistle [due to the turbos?]).

There is a definite difference in the general sound of Sulzer v EE engines.

[woodenhead]

1 hour ago, keefer said:

They might not sound exactly the same but all Sulzer locos sounds similar, inc. the smaller engined cl.24-27 (6-cyl) and 33 (8-cyl).

Similarly, the EE locos sound similar to each other - cl.20, 31, 37, 40 & 50 (though 20s  & 40s have a noticeable 'tweet' or whistle [due to the turbos?]).

There is a definite difference in the general sound of Sulzer v EE engines.

Except 20906 that works at Earles Sidings - it doesn't sound like any other class 20 I've heard, have they done something to it does anyone know?

[DY444]

On 03/03/2023 at 12:59, pheaton said:

ETH alternator fitted (not 47/4s) 47s have an idle speed of 325 RPM this was added to avoid overloading the engine at idle with the ETH ON

 

I think you mean "not 47401 - 47420" rather than "not 47/4s".  All 47/4s from 47421 had the alternator.

Edited March 5, 2023 by DY444

[Matt37268]

On 03/03/2023 at 20:24, woodenhead said:

Except 20906 that works at Earles Sidings - it doesn't sound like any other class 20 I've heard, have they done something to it does anyone know?

I think it might have had some additional mods to its silencing? 
 

[The Johnster]

There is certainly a 'family' sound both to Sulzer and to EE locos (except Deltics, which sound more like an approaching squadron of Lancasters), but it differs between classes for reasons such as those very illuminating ones stated above.  But I would note a very distinct difference within the Sulzer 'family' between the Type 4s and the Type 2s, the Type 2s sounding much more 'chattery' and uneven on tickover (slower tickover rpm?).  There also seemed to be a Maybach/Paxman sort of sound as well, more sort of 'jingy' with a soft j.  I'd have said it was peculiar to hydraulics, but the HST Paxmans had it as well.

 

Were I modelling DCC diesel era with sound, I'd recommend using sound chips particular to the class modelled, not a 45 noise from a 47 or 46.  If the sound files are correct, you should be able to hear the difference, though the tiny speakers don't help.  I'd rather have sounds through hi-fi headphones, proper headphones that can handle some bass, not the squeaky little earbuds you buy in pound shops.  Especially if Deltics are involved...

[New Haven Neil]

3 hours ago, The Johnster said:

But I would note a very distinct difference within the Sulzer 'family' between the Type 4s and the Type 2s,

 

The type 4's have twice as many cylinders.....effectively two 6 cylinder in-line engines side by side, geared together.  Hence the difference.  The EE engines are mostly V configuration, so completely different in firing order and hence sound,  from 8 cylinders in a 20, to 16 in a 40.  The whistling turbos are normally made by Napiers, I suffered with the *&^%$£" things at sea.

[rogerzilla]

Agree on the type 2s having an uneven idle (or on low power).  The class 24 at the GWSR is noticeably lumpy compared to the 45 or 47 that were also running at the laat diesel gala.

 

I think EE engines are quite different-sounding - class 20s are called Choppers and class 37s Tractors for a reason.  The V16 in the class 50 is smoother but you can (or could, in the 1980s) hear it nearly a mile away at 100mph.

 

The Metrovicks were going to get uprated class 20 engines (EE provided a quote just before BR decided to pull the plug on the smaller classes).  No idea what they would have sounded like.

[pheaton]

14 hours ago, The Johnster said:

There is certainly a 'family' sound both to Sulzer and to EE locos (except Deltics, which sound more like an approaching squadron of Lancasters), but it differs between classes for reasons such as those very illuminating ones stated above.  But I would note a very distinct difference within the Sulzer 'family' between the Type 4s and the Type 2s, the Type 2s sounding much more 'chattery' and uneven on tickover (slower tickover rpm?).  There also seemed to be a Maybach/Paxman sort of sound as well, more sort of 'jingy' with a soft j.  I'd have said it was peculiar to hydraulics, but the HST Paxmans had it as well.

 

Were I modelling DCC diesel era with sound, I'd recommend using sound chips particular to the class modelled, not a 45 noise from a 47 or 46.  If the sound files are correct, you should be able to hear the difference, though the tiny speakers don't help.  I'd rather have sounds through hi-fi headphones, proper headphones that can handle some bass, not the squeaky little earbuds you buy in pound shops.  Especially if Deltics are involved...

a 6lda has the same tick over as a non ETH 12lda 250 rpm, remember type 2s are completely unsilenced they will sound a lot different to a type 4 even though....a 44 45 and 47 is effectively two 6ldas in the same crankcase..

 

someone mentioned 24081s lumpy tick over....this is because its governor drive is worn, 24s are still on the original bevel drive for the governors whereas all the other type 2s were updated to the spline drive this means its much more suseptible to wear and as a result 24081s governor has been removed and sent away for overhaul.

 

26043 also had a lumpy tick over this was due to a fuel pump being out of calibration on one of the cylinders.

[Davexoc]

12 hours ago, rogerzilla said:

I think EE engines are quite different-sounding - class 20s are called Choppers and class 37s Tractors for a reason.  The V16 in the class 50 is smoother but you can (or could, in the 1980s) hear it nearly a mile away at 100mph.

 

You could sometimes hear them running through Princes Risborough over in Chinnor, 4-5 miles away. Probably because there is no silencer, and very little distance from turbo-charger to exhaust port, so little that if you want to check the exhaust side blades, you could reach in and feel each blade while turning it over by hand, (cold of course).

[Ken.W]

Comparing the sound of the Sulzer type 2s with type 4s, bear in mind that running at the same rpm the type 2 has half the number of cylinders firing

[rodent279]

3 hours ago, Ken.W said:

Comparing the sound of the Sulzer type 2s with type 4s, bear in mind that running at the same rpm the type 2 has half the number of cylinders firing

True, but possibly they fire in pairs? Maybe the experts on here can enlighten us?

(Not that I'm saying they should sound the same, because clearly they do not!)

[Davexoc]

6 hours ago, rodent279 said:

True, but possibly they fire in pairs? Maybe the experts on here can enlighten us?

(Not that I'm saying they should sound the same, because clearly they do not!)

 

The DerbySulzers website does mention that the synchronisation was changed to reduce vibration in the class 44 section.

In theory you would set the two banks to give you one cylinder firing every 60 degrees, 60 x 12 = 720 or two revolutions per crankshaft so 1 full four stroke cycle.

[Covkid]

On 09/03/2023 at 15:53, rodent279 said:

True, but possibly they fire in pairs? Maybe the experts on here can enlighten us?

(Not that I'm saying they should sound the same, because clearly they do not!)

 

On 09/03/2023 at 22:30, Davexoc said:

The DerbySulzers website does mention that the synchronisation was changed to reduce vibration in the class 44 section.

In theory you would set the two banks to give you one cylinder firing every 60 degrees, 60 x 12 = 720 or two revolutions per crankshaft so 1 full four stroke cycle.

 

My dad always told me the big Sulzers sounded different, and I remember him telling me about a trip back from Bristol behind a peak back in the mid 1960s.  He said this loco sounded like a jubilee as it climbed up Filton bank.  I never thought anymore of it until last year when I saw a video of D4 at a gala at the Severn Valley railway.  It sounded very very different to the LDA powered type 4s I remember - like two 6LDAs welded together. Apparently the owners have fitted it with the original LDA phasing gears which alters the timing and thus the sound of D4.

 

   

 

[adb968008]

On 03/03/2023 at 19:09, keefer said:

They might not sound exactly the same but all Sulzer locos sounds similar, inc. the smaller engined cl.24-27 (6-cyl) and 33 (8-cyl).

Similarly, the EE locos sound similar to each other - cl.20, 31, 37, 40 & 50 (though 20s  & 40s have a noticeable 'tweet' or whistle [due to the turbos?]).

There is a definite difference in the general sound of Sulzer v EE engines.

I always thought Peaks to be a bit lame on the sound side… a muted 47.

 

24/25’s seem similar, but 26/27 are different… they sound less knackered that the 24/25’s.

 

For EE machines, no difficulty detecting the differences in sound there, they are very distinct.