The mighty Class 74 (some questions!)

[Big Jumby 74]

Are there any recordings of a 74 on diesel still in existence?

My guess that's a bit of a needle in the old haystack! Very small fleet, only likely booked to be on diesel in a small number of locations, namely Waterloo (to prevent gapping when shunting to/from loco dock/North sidings), Clapham Yard (similar reasons) and down in the Docks.

== Doublepost prevention - post automatically merged: 10 Sep 2025 ==

the twenty chime whistles ended up on the Isle of Wight, where they were fitted to the class 485 and 486 "Standard" tube stock.

That sounds familiar, although never knew they came from the 74 programme. No surprise though!

 

[Harlequinuk]

Thats a 14 at full chat ; maybe for engine sound alone?

 

[D7666]

Are there any recordings of a 74 on diesel still in existence? I

Yes.

I have one on diesel and one on electric.

BUT they were not made by me, they were kindly sent to me some time ago when a similar question came up in another discussion. Please do not ask me to send them or upload them anywhere.

The booster set made a lot of noise, it masks out much of the diesel engine sound especially if you were close up to one; a 74 diesel could more clearly be heard at some distance away from it.

Yes the engine is the same model as in a 14 but I doubt anyone close to a 74 could identify that unless they were very familiar with a 14. If you played a 74 on diesel anonymously to anyone who had never heard one I'd suggest the most likely reaction is WTF is that where WTF is not a TLA for a previously unknown station.
_

And second thought - why was the power so low at the rail?

Because the transmission is inefficient.

Booster set is actually inefficient on electric as well as on diesel. On electric, instead of traxction current > traction motors, it does traction current > booster motor > booster genertor > traction motor, each step has a 9% efficiency loss.

No-one really would start off to build from scratch a new electro diesel with a diesel engine driving a booster set. Think about it - the booster (as in CC and HA) was a means to bridge third rail gaps, so was the diesel engine in JA/JB, therefore since you have a diesel engine anyway you don't need a booster. The booster was retained only to avoid replacing the entire control system.

74s were a bit too early to have had power electronics; they'd have been ideal and I suggest lasted a bit longer than they did if they had had electronics, if it were reliable. 74s did have power control electronics but not actual power electronics. To have completely replaced a 71s booster set in the 74 rebuilds would have meant a large resistor camshaft control system which didnot come cheap, and the Bomo line electrification was done on a shoe string budget.

 

[Harlequinuk]

Seems even worse on diesel with nearly 50% drop at the rail

re the model : https://www.roads-and-rails.co.uk/p...lass-74-electro-diesel?variant=54719704072577

 

[D6130]

Booster set is actually inefficent on electric as well as on diesel. On electric, instead of traxction current > traction motors, it does traction current > booster motor > booster genertor > traction motor, each step has a 9% efficiency loss.

Quite! The booster sets on the 71s were designed to just carry the loco/train across long gaps in the conductor rail, whereas the 74s also needed "last mile" power to drag boat trains around the docks. I can only assume that a direct engine -> generator -> traction motor linkage - in addition to the booster and flywheel - would have been too expensive and/or would have taken up too much space in the confined body shell.

 

[Harlequinuk]

@D7666

Found this video and oh golly gosh, that booster is like a jet engine!!

having spoken with legomanbiffo, he has a few recordings to both the 14 engine and the 71 booster , and would be happy to combine them for a more authentic 74 sound for a dcc sound file for model railway.

== Doublepost prevention - post automatically merged: 16 Sep 2025 ==

Have aa name (maybe)? - Graham Arnold? He might actually have a recording of 74002?

 

[Harlequinuk]

A little addon ;

thank you to the user who dropped me a message with the public location of the 3x Class 74 engine sound files recorded and uploaded by Grahame Arnold himself. My sound `fetish` is satisfied

 

[Harlequinuk]

I hope i can be forgiven, but i have been pointed to an old video - which has 2 or maybe 3 Class 74s (and others) in it! Please slow the video down to 0.25 speed, and its a case of spot all the old stock!

 

[75A]

I hope i can be forgiven, but i have been pointed to an old video - which ahs 2 or maybe 3 Class 74s (and others) in it! Please slow the video down to 0.25 speed, and its a case of spot all the old stock!

Thanks for this, watched it twice, once @ speed and then slowed it down.


























iwice

 

[Big Jumby 74]

I hope i can be forgiven, but i have been pointed to an old video - which has 2 or maybe 3 Class 74s (and others) in it! Please slow the video down to 0.25 speed, and its a case of spot all the old stock!

Thanks for that. Views inside Waterloo box a trip down memory lane. As for loco's/stock, if I may add a few comments;

At 0.17 a class 73 is seen departing down the DMF on a (presumed) passenger (as opposed to empty) service, but a lack of a van (GUV) at the London end suggests this is not a boat train.

At 0.20-0.24 a class 74 can be seen at the top end of platform 9, awaiting a path to either shunt to the loco dock or run light engine to Clapham yard.

At 0.55 a class 74 on what appears to be a van train (all blue vehicles, a GUV with 'Newspaper' wording on the rear) passing West London Junction on the UMF line. View taken from West London box.

At 1.23 another class 74 passing West London Junction on what appears to be an Up passenger service. A lack of a van behind the loco suggests again, this is not a boat train.

At 1.33 at Vauxhall, a DMS service seen heading away from platform 8 (left of image) has one of the (then) few remaining 41xx numbered 4 SUB's on the rear.

Hope these obs are of some interest.

 

[Sun Chariot]

0.55 a class 74 on what appears to be a van train (all blue vehicles, a GUV with 'Newspaper' wording on the rear) passing West London Junction on the UMF line. View taken from West London box.

That rake, I see what appears to be two intermediate all-blue composite carriages - and so I wondered if it's actually a pair of unrefurbished 4-CEP units? I've discounted 4TCs (corridor first, not a corridor composite); I also discounted a 4VEP and 4CIG (composites were in each driving trailer).

At 1m 00s an interesting 12 car rake passes, right to left. It seems (on my small phone-screen!) to be:
2EPB all-blue
2HAP all-green
4EPB all-blue
4CEP or 4REP blue-grey

 

[Big Jumby 74]

At 1m 00s an interesting 12 car rake passes, right to left. It seems (on my small phone-screen!) to be:
2EPB all-blue
2HAP all-green
4EPB all-blue
4CEP or 4REP blue-grey

Have re run that at slow speed several times. IMO, it is formed 2 HAP + 2 HAP (first class yellow stripe on both), + 4 VEP (yellow stripes can just be made out on the inner ends of cars 1 & 4) + (4 CEP?). My question mark over the latter is that I can not see any first class yellow stripe, but the brake vans are at the out ends of the unit, which matches a CEP in original configuration. If it wasn't for the quoted date (1970), I would have said this last unit was a BR series 4 EPB in blue/grey, which would then conflict with an all blue VEP, so date wise that doesn't match? Hence my thinking 4 CEP?

BOLD; My edit.

 

[Sun Chariot]

NIce one @Big Jumby 74 thanks.
It was the blue-grey 4 car unit in the 1970 film, which piqued my interest. I only knew of 4REPs in blue-grey at that time.
I do concur with you, those look like the 4CEP DMBS as-buit, rather than 4REP DMS saloon.
I'll watch it on my big screen in the week, as that'll be easier to see the other HAP + VEP in the consist.

 

[Big Jumby 74]

I do concur with you, those look like the 4CEP DMBS as-buit, rather than 4REP DMS saloon.

If a REP were involved, virtually everything else (in that formation) would have had to be isolated due to the draw on the traction current. Reference BR booklet BR. 29857, 'Southern Reg., Electrified Lines Working Instructions - instruction # 47, Traction Current loading' and subsequent amendments.

(I kept most things I was issued with in my early days on the job, not so much in later years - too much paperwork etc!)

For topical interest, supplement #2 of same dated Feb 1981, saw the removal of references to classes 71 & 74 in the above instruction, and the complete removal of instruction #50 which related to overhead conductor wires - think class 71 and certain parts of Kent.

 

[Sun Chariot]

If a REP were involved, virtually everything else (in that formation) would have had to be isolated due to the draw on the traction current. Reference BR booklet BR. 29857, 'Southern Reg., Electrified Lines Working Instructions - instruction # 47, Traction Current loading' and subsequent amendments.

(I kept most things I was issued with in my early days on the job, not so much in later years - too much paperwork etc!)

For topical interest, supplement #2 of same dated Feb 1981, saw the removal of references to classes 71 & 74 in the above instruction, and the complete removal of instruction #50 which related to overhead conductor wires - think class 71 and certain parts of Kent.

I love insightful backstories like this, as I hadn't even started "O" Levels in 1981.

 

[Harlequinuk]

Yet more research has yielded a chap called Brian Denton:

BR884 E6104 @Willesden 9-73

Kicking off a small collection of Southern Region electric locos. HA and HB (later class 71 and 74) Taken at work the cement empties from Bevous Park ( Southampton Up TC ) have just been set back on the Goods Road. The HB will run off towards the return load loaded cement wagons from Tring on...

www.flickr.com

Many many photos, and yes thats a 74 on freight

and

BR988 74009 @ Terminus 4-6-77

I rate this as my best all time class 74 shot. The former Southampton Terminus shut in 1966 but the platforms and structure were still intact 11 years later. Note on the extreme left Chapel Goods Depot was still in use for NCL but no longer served by the railway.

www.flickr.com

 

[Strathclyder]

Yet more research has yielded a chap called Brian Denton:

BR884 E6104 @Willesden 9-73

Kicking off a small collection of Southern Region electric locos. HA and HB (later class 71 and 74) Taken at work the cement empties from Bevous Park ( Southampton Up TC ) have just been set back on the Goods Road. The HB will run off towards the return load loaded cement wagons from Tring on...

www.flickr.com

Many many photos, and yes thats a 74 on freight

and

BR988 74009 @ Terminus 4-6-77

I rate this as my best all time class 74 shot. The former Southampton Terminus shut in 1966 but the platforms and structure were still intact 11 years later. Note on the extreme left Chapel Goods Depot was still in use for NCL but no longer served by the railway.

www.flickr.com

He has some cracking shots of 71s/74s for sure, these are my personal favourites (including that one of E6104 at Willesden; can't be too many photos of 74s there).

BR921 74001 @ Ocean Terminal 25-6-77

Shunting at the Ocean Terminal. East Docks pilot 07001 has positioned the GUV after loading, which will be attached to the Boat Train loco 74001. The much loved QE2 was still doing the trans-Atlantic run what she was built for at this stage. Now I wish I had recorded every day shunting in the...

www.flickr.com

BR910 74001 @ Canute Road 25-6-77

We often see pictures of trains crossing Canute Road , but shots showing Canute Road Signalbox are much less often featured. Cunard Boat Train leaving Southampton Eastern Docks for Waterloo is one of my prized memories from the period

www.flickr.com

BR982 74005 Papers @ Waterloo 10-76

The 0215 Fast Papers, it ran to Bournemouth, the after a traction change principle stations to Weymouth.

www.flickr.com

 

[Harlequinuk]

1 for the experts;

How is train ETH rating calculated? After some more research i have found the 74 had electric train heating of 400 amps; what would that be as a rating? Would also explain how it really would give low performance on diesel. Could you image the struggle, for a loaded boat train, out of Weymouth, in the winter!

 

[AndrewE]

1 for the experts;

How is train ETH rating calculated? After some more research i have found the 74 had electric train heating of 400 amps; what would that be as a rating? Would also explain how it really would give low performance on diesel. Could you image the struggle, for a loaded boat train, out of Weymouth, in the winter!

for a temporary increase in tractive effort the driver could turn off the ETH - unless the kitchen car depended on it!

 

[Gloster]

It was not uncommon for the eth to be on while the train was at the platform and then switched off when the loco need maximum power. The residual heat should last long enough not to cause the passengers to freeze their nadgers off and they would presumably prefer to be moving rather than sitting in the warm and not moving. It occasionally happened at Salisbury if a train heading for Basingstoke via Porton Bank was unusually long.

The Class 74 had an eth index of 66 and each coach would have a number as well: a Mark 1 TSO was 4. The total of all the coaches should not pass 66 if hauled by a 74.

As said above, visits by 74 were very, very rare. If they ever had to work a full-length train out of the town, you would just have had to improvise.

 

[Rescars]

for a temporary increase in tractive effort the driver could turn off the ETH - unless the kitchen car depended on it!

Nothing like propane gas to guarantee a warming cuppa!

 

[Harlequinuk]

Been reading they were far more common out of Southampton - the lack of gradient and short distance from the Eastern / Western docks to the mainline was deemed `ok` for diesel, whereas the climb from Weymouth to the `juice` was, at times, too much, and thats when the engine actually started.

edit:

Still trying to find that rare photo of a 74 on the Weymouth tram line!

 

[Helvellyn]

Been reading they were far more common out of Southampton - the lack of gradient and short distance from the Eastern / Western docks to the mainline was deemed `ok` for diesel, whereas the climb from Weymouth to the `juice` was, at times, too much, and thats when the engine actually started.

But it wasn't just a climb out of Weymouth - that diesel would have been required all the way to Branksome if a 74 had got to Weymouth.

 

[Gloster]

But it wasn't just a climb out of Weymouth - that diesel would have been required all the way to Branksome if a 74 had got to Weymouth.

Once you are over the top of Bincombe it is undulating downwards and so not a severe problem until Poole, but after that you have the short but sharp Parkstone Bank and you can’t take a run at that because of the curve through Poole station. Getting to Weymouth wouldn’t be that easy either as it is generally upwards from Wareham, ending with a brief 1 in 91 to Bincombe and you can’t take a run at that either because of the curve between Dorchester South and Junction.

 

[D6130]

I'm not aware of a 74 ever having reached Weymouth and have never seen a photo of one West of Poole....but I'm happy to be proved wrong.

 

[Gloster]

I'm not aware of a 74 ever having reached Weymouth and have never seen a photo of one West of Poole....but I'm happy to be proved wrong.

See #74.

 

[D6130]

See #74.

Ah yes....so many posts ago that I had forgotten about that!

 

[Harlequinuk]

Did the booster run when in diesel? Just at a lower rpm than when on electric?

== Doublepost prevention - post automatically merged: 17 Dec 2025 ==

Have managed to stumble across some more photos of the Mighty `BigED`

including 2 of freight working!

https://www.dawlishtrains.com/class-741.html

 

[D6130]

Did the booster run when in diesel? Just at a lower rpm than when on electric?

== Doublepost prevention - post automatically merged: 17 Dec 2025 ==

Have managed to stumble across some more photos of the Mighty `BigED`

including 2 of freight working!

https://www.dawlishtrains.com/class-741.html

Great photos....thanks for posting!

 

[Harlequinuk]

Now the models are out, actual engine sounds are available ; thank you to Grahame Arnold for being the inspiration (and others of course) and digging out the cassette tapes!