Southern Region Class 73 & 74 locos

[mor100]

Morning all,

Does anyone know what the top speed of the Southern Region (SR)'s classes 73&4 were when operating on their diesel engines?

I'm asking as a model railway enthusiast, and just debating whether these locos have a place on my layout (which has no third rail power)...

Thanks in advance, Matt.

 

[73001]

73s have made it to various unelectrified areas recently but also in the early days (although not as wide spread). I think they had a tendency to overheat if used on diesel for long periods but you could consider short engineering trains to be semi realistic.

 

[mor100]

73s have made it to various unelectrified areas recently but also in the early days (although not as wide spread). I think they had a tendency to overheat if used on diesel for long periods but you could consider short engineering trains to be semi realistic.

Thanks(!) Much appreciated. M

 

[36270k]

Top speed on diesel was the same as on electric.
80 mph for 73/0
90 mph for 73/1 and 74
They only could reach top speed on diesel when running light.

 

[mor100]

Top speed on diesel was the same as on electric.
80 mph for 73/0
90 mph for 73/1 and 74
They only could reach top speed on diesel when running light.

Great - thanks. M

 

[bangor-toad]

Hi,
I've always had a soft spot for the 73's. Here are some images I've found online (none are mine - all credits to the photographers)

A pair of 73's on a Birmingham New Street to I believe Portsmouth (from 1982)
A Pair of ED's From Birmingham
(A friend of a friend claims to have been the driver that took the pair up to Birmingham in the first place. I have no way at all of verifying that!)

Shunting the VSOE in Northampton
73 101 'The Royal Alex' at Northampton

Test train in Derbyshire (2014)
South at Duffield

Last month near Manchester
73963 & 73965 Altrincham


Even the un-refurbished ones got out of the Southern Region occasionally...
Cheers,
Mr Toad

 

[david1212]

Hi,
I've always had a soft spot for the 73's. Here are some images I've found online (none are mine - all credits to the photographers)

A pair of 73's on a Birmingham New Street to I believe Portsmouth (from 1982)
A Pair of ED's From Birmingham
(A friend of a friend claims to have been the driver that took the pair up to Birmingham in the first place. I have no way at all of verifying that!)

The northbound working at Banbury
21st August 1982 Banbury Class 73s - 73 134(F) and 73 108(R) 1105 Portsmouth Harbour to Manchester Piccadilly.

Shunting the VSOE in Northampton
73 101 'The Royal Alex' at Northampton

Test train in Derbyshire (2014)
South at Duffield

I don't of course know the era you are modelling but in the examples above running on the original ( theoretically given some comments that the actual maximum power was rather less ) 600hp engines where as below updated with the 1600hp MTU 8V 4000 R43L.

On paper as built a pair had similar performance to a class 24 - 27. If one was ailing the other would be doing rather more than 50% of the work further increasing the risk of overheating on top of trying to minimise the time loss if the booked haulage was higher power/performance.

Last month near Manchester
73963 & 73965 Altrincham

Even the un-refurbished ones got out of the Southern Region occasionally...
Cheers,
Mr Toad

 

[Bevan Price]

The northbound working at Banbury
21st August 1982 Banbury Class 73s - 73 134(F) and 73 108(R) 1105 Portsmouth Harbour to Manchester Piccadilly.



I don't of course know the era you are modelling but in the examples above running on the original ( theoretically given some comments that the actual maximum power was rather less ) 600hp engines where as below updated with the 1600hp MTU 8V 4000 R43L.

On paper as built a pair had similar performance to a class 24 - 27. If one was ailing the other would be doing rather more than 50% of the work further increasing the risk of overheating on top of trying to minimise the time loss if the booked haulage was higher power/performance.

Rather worse than a Class 24-27, because a pair of 73s weighed about double the weight of a single 24-27.

 

[Richard Scott]

Rather worse than a Class 24-27, because a pair of 73s weighed about double the weight of a single 24-27.

Did have a pair of 73s on diesel on around load 11/12. Maxed out at 62mph.

 

[30907]

Top speed on diesel was the same as on electric.
80 mph for 73/0
90 mph for 73/1 and 74
They only could reach top speed on diesel when running light.

...when surely they weren't allowed to?

 

[Richard Scott]

...when surely they weren't allowed to?

Probably not, aren't light locos (older ones with tread brakes) limited to 75mph due to brake force issues?

 

[Cowley]

Could a pair of 73s running at 90mph on the 3rd rail lift the shoes and switch to diesel on the fly at somewhere like Worting Junction?
I feel like I read about something like that happening on a railtour back in the 1980s maybe?

 

[Richard Scott]

Could a pair of 73s running at 90mph on the 3rd rail lift the shoes and switch to diesel on the fly at somewhere like Worting Junction?
I feel like I read about something like that happening on a railtour back in the 1980s maybe?

You can do that, I believe but would take a while for diesels to run up as there's an autostart on them that runs a priming pump first and only starts the engine when a preset oil pressure is reached. If you had a willing second man send them into the engine room and manually prime, about 100 strokes of the handle should do it, engine will then start straight away!!!

 

[Cowley]

You can do that, I believe but would take a while for diesels to run up as there's an autostart on them that runs a priming pump first and only starts the engine when a preset oil pressure is reached. If you had a willing second man send them into the engine room and manually prime, about 100 strokes of the handle should do it, engine will then start straight away!!!

Interesting stuff Richard

 

[12LDA28C]

Hi,
I've always had a soft spot for the 73's. Here are some images I've found online (none are mine - all credits to the photographers)

A pair of 73's on a Birmingham New Street to I believe Portsmouth (from 1982)
A Pair of ED's From Birmingham
(A friend of a friend claims to have been the driver that took the pair up to Birmingham in the first place. I have no way at all of verifying that!)

Shunting the VSOE in Northampton
73 101 'The Royal Alex' at Northampton

Test train in Derbyshire (2014)
South at Duffield

Last month near Manchester
73963 & 73965 Altrincham


Even the un-refurbished ones got out of the Southern Region occasionally...
Cheers,
Mr Toad

A pair of 73s attempted to reach Birmingham on a XC working in the late 90s but I believe they expired at Fenny Compton.

 

[Cowley]

A pair of 73s attempted to reach Birmingham on a XC working in the late 90s but I believe they expired at Fenny Compton.

We had 73003 at the Mid Hants for a while in the 1990s and I remember it used to struggle with more than about four coaches on the 1 in 60 stretches. I think it used overheat because they didn’t have particularly large radiators.

 

[nw1]

Hi,
I've always had a soft spot for the 73's. Here are some images I've found online (none are mine - all credits to the photographers)

A pair of 73's on a Birmingham New Street to I believe Portsmouth (from 1982)
A Pair of ED's From Birmingham
(A friend of a friend claims to have been the driver that took the pair up to Birmingham in the first place. I have no way at all of verifying that!)

Flickr does confirm that they were earlier on the northbound Portsmouth-Manchester and, in this photo, the corresponding southbound working.

 

[36270k]

Could a pair of 73s running at 90mph on the 3rd rail lift the shoes and switch to diesel on the fly at somewhere like Worting Junction?
I feel like I read about something like that happening on a railtour back in the 1980s maybe?

They would start the diesel engine a few minutes before.
Then at the end of the 3rd Rail, close the electric controller and open the diesel controller.

 

[Richard Scott]

They would start the diesel engine a few minutes before.
Then at the end of the 3rd Rail, close the electric controller and open the diesel controller.

A while since been on a 73 but thought power controller had to be in EO to start the diesel engine?

 

[mor100]

Hi,
I've always had a soft spot for the 73's. Here are some images I've found online (none are mine - all credits to the photographers)

A pair of 73's on a Birmingham New Street to I believe Portsmouth (from 1982)
A Pair of ED's From Birmingham
(A friend of a friend claims to have been the driver that took the pair up to Birmingham in the first place. I have no way at all of verifying that!)

Shunting the VSOE in Northampton
73 101 'The Royal Alex' at Northampton

Test train in Derbyshire (2014)
South at Duffield

Last month near Manchester
73963 & 73965 Altrincham


Even the un-refurbished ones got out of the Southern Region occasionally...
Cheers,
Mr Toad

Thanks so much for these photos. The first one is v inspirational - I didn't think about double-headed running, which presumably compensates for their reliance on diesel running in the absence of a third rail.

Rather worse than a Class 24-27, because a pair of 73s weighed about double the weight of a single 24-27.

Did have a pair of 73s on diesel on around load 11/12. Maxed out at 62mph.

Thanks.

 

[Shimbleshanks]

I seem to recall that there was a period after the Class 442s were introduced and third rail extended to Weymouth when they were used in pairs under diesel power west of Bournemouth towing the 442s because there was some problem with energising the electrification. Can't remember the full details now but would have been sometime in the 1980s?

 

[Cowley]

I seem to recall that there was a period after the Class 442s were introduced and third rail extended to Weymouth when they were used in pairs under diesel power west of Bournemouth towing the 442s because there was some problem with energising the electrification. Can't remember the full details now but would have been sometime in the 1980s?

I had quite a few runs on them back then (1988 ish?) but I thought they were operating purely on electric and it was mainly due to them reusing the traction motors on the 4REPs for the 442s?

 

[Big Jumby 74]

I seem to recall that there was a period after the Class 442s were introduced and third rail extended to Weymouth when they were used in pairs under diesel power west of Bournemouth

Only as far as Poole (on the juice) on a planned basis. If that happened (West of Poole) it was not by design, but (perhaps) a 'Control' move due to 442 failure?

I had quite a few runs on them back then (1988 ish?) but I thought they were operating purely on electric and it was mainly due to them reusing the traction motors on the 4REPs for the 442s?

Spot on. Certain diagrams (Poole's) were diagrammed 2 x 73/8TC, in order that the REP withdrawal programme could continue to supply components for 442's. Can still remember diagramming same, as we issued 'Special (STP) Notices' that endured for several weeks at a time, amending the base plan, which reduced the workload on the STP planners to a degree, saving them having to re issue same every week/weekend.

 

[contrex]

Top speed on diesel was the same as on electric.
80 mph for 73/0
90 mph for 73/1 and 74
They only could reach top speed on diesel when running light.

But light engines are usually restricted to a somewhat low max speed on account of the low amount of brake force available, or so I thought?

 

[Richard Bishop]

Could a pair of 73s running at 90mph on the 3rd rail lift the shoes and switch to diesel on the fly at somewhere like Worting Junction?
I feel like I read about something like that happening on a railtour back in the 1980s maybe?

5th January 1985 73003/005 on 1Z25 the Kent Hopper between Faversham to Ashford via Canterbury and Dover changed from electric to diesel power on the fly owing to weather conditions (heavy snow falls in eastern Kent). Tour had started at Plymouth with no problems a far as London ,as we travelled east with the 73’s top and tailed via Sittingbourne it was decided that there would be a change of plan.73005 should have t&t with 33207 so we could do the Folkestone harbour branch but that changed to have the 73’s in multiple and miss the harbour branch. They started on electric but soon changed to diesel as the snow covered the third rail.33207 took over at Ashford and took the train to Reading. Other locomotives involved on tour were 31127/226 from Plymouth to Southall on the outward and returning from Reading to Bristol TM for 47619 to Plymouth.My memory of is that there was virtually no snow in London but it got progressively worse as we travelled eastwards to a total whiteout between Faversham and Ashford. On the return the snow was conspicuous by its abscence in London and further west,being very localised to East Kent.

 

[D6975]

Only as far as Poole (on the juice) on a planned basis. If that happened (West of Poole) it was not by design, but (perhaps) a 'Control' move due to 442 failure?

Spot on. Certain diagrams (Poole's) were diagrammed 2 x 73/8TC, in order that the REP withdrawal programme could continue to supply components for 442's. Can still remember diagramming same, as we issued 'Special (STP) Notices' that endured for several weeks at a time, amending the base plan, which reduced the workload on the STP planners to a degree, saving them having to re issue same every week/weekend.

Close...
Initially what they did was to replace one power car of a 4REP (London end) with a 73 to release one set of traction motors. These 3REP73s were used just like a 4REP and were used on Weymouth services as far as Bournemouth. Only a few pairs of 73s ran in the early stages. As the 442 program needed more traction motors, so the transition to pairs of 73s happened and the remaining REP coaches and TCs appeared in all sorts of wonderful combinations, an extended TC including a REP buffet car even ran for a short time. Towards the end they were using a load of 73s every day, so much so that you even got the occasional GatEx 73 putting in an appearance.

ps I spent a lot of time on these services, getting the 73/1s for haulage.

 

[Richard Scott]

Close...
Initially what they did was to replace one power car of a 4REP (London end) with a 73 to release one set of traction motors. These 3REP73s were used just like a 4REP and were used on Weymouth services as far as Bournemouth. Only a few pairs of 73s ran in the early stages. As the 442 program needed more traction motors, so the transition to pairs of 73s happened and the remaining REP coaches and TCs appeared in all sorts of wonderful combinations, an extended TC including a REP buffet car even ran for a short time. Towards the end they were using a load of 73s every day, so much so that you even got the occasional GatEx 73 putting in an appearance.

ps I spent a lot of time on these services, getting the 73/1s for haulage.

I remember in 1987 the REPs were still running the Waterloo to Weymouth trains as far as Bournemouth and the Waterloo to Bournemouth semi-fasts were pairs of 73s on 8TC units. By early 1988 the 73+3REP combination was commonplace on the Weymouth services.

 

[Graham H]

Could a pair of 73s running at 90mph on the 3rd rail lift the shoes and switch to diesel on the fly at somewhere like Worting Junction?
I feel like I read about something like that happening on a railtour back in the 1980s maybe?

I was on a Portsmouth to north train, the previously mentioned 21 Aug 1982 one and they left Guildford on electric and as I was hanging out of the window watching I know they switched to diesel on the fly during the slow down at the site of the former junction between Wanborough and Ash. The other interesting observation was that pretty much all coaches seemed to be CK with 1st class downgraded by paper notices so a very interesting and comfortable trip.

 

[Cowley]

5th January 1985 73003/005 on 1Z25 the Kent Hopper between Faversham to Ashford via Canterbury and Dover changed from electric to diesel power on the fly owing to weather conditions (heavy snow falls in eastern Kent). Tour had started at Plymouth with no problems a far as London ,as we travelled east with the 73’s top and tailed via Sittingbourne it was decided that there would be a change of plan.73005 should have t&t with 33207 so we could do the Folkestone harbour branch but that changed to have the 73’s in multiple and miss the harbour branch. They started on electric but soon changed to diesel as the snow covered the third rail.33207 took over at Ashford and took the train to Reading. Other locomotives involved on tour were 31127/226 from Plymouth to Southall on the outward and returning from Reading to Bristol TM for 47619 to Plymouth.My memory of is that there was virtually no snow in London but it got progressively worse as we travelled eastwards to a total whiteout between Faversham and Ashford. On the return the snow was conspicuous by its abscence in London and further west,being very localised to East Kent.

Fantastic, and…

I was on a Portsmouth to north train, the previously mentioned 21 Aug 1982 one and they left Guildford on electric and as I was hanging out of the window watching I know they switched to diesel on the fly during the slow down at the site of the former junction between Wanborough and Ash. The other interesting observation was that pretty much all coaches seemed to be CK with 1st class downgraded by paper notices so a very interesting and comfortable trip.

Also fantastic.

I just love hearing those sorts of stories.

 

[6Gman]

I was on a Portsmouth to north train, the previously mentioned 21 Aug 1982 one and they left Guildford on electric and as I was hanging out of the window watching I know they switched to diesel on the fly during the slow down at the site of the former junction between Wanborough and Ash. The other interesting observation was that pretty much all coaches seemed to be CK with 1st class downgraded by paper notices so a very interesting and comfortable trip.

I think there was a surplus of CKs (Corridor Composites) and on the LMR - at least - there were a couple of excursion/relief sets that were largely made up of CKs. Something like BSK/ 7xCK/ BSK.