Service History BR Class 73 - BRM February 2016

[bécasse]

Andy York has provided a nice potted history of the class 73 electro-diesels in the February 2016 BRM to sit alongside Ben York's review of the new Dapol model in the same issue.

 

However, he repeats the old myth that "their boxy appearance was a result of being built to the narrow profile required for the restricted Tunbridge Wells-Hastings line". Both the original JA (73/0) and the subsequent JB (73/1) classes were, of course, narrow enough in profile to work along the Hastings line, but the reason for their slimness was more interesting because they were designed not to the SR Restriction 0 loading gauge (which was required for the Hastings line) but to the then current Isle of Wight loading gauge which was equally slim but also slightly more height constrained - Ryde Esplanade Tunnel being then, as now, the limiting factor.

 

The original design work was done at Eastleigh not for electro-diesel locomotives but for diesel-electric motor luggage vans intended for use in the Isle of Wight to replace the ailing O2 tanks. That particular scheme fell by the wayside, but when the need for electro-diesels as part of the Kent Coast scheme became clear (typically to work early morning newspaper trains because they could pass through electrical possessions) it was realised that the design work already done needed little alteration to create the JA class, not much more in fact than the provision of shoe beams, traction cabling and head code displays and the deletion of the proposed luggage van doors (but with their windows retained).

[Graham_Muz]

I would be interested to see the evidence of your theory above. Your post has been discussed on the SeMG email group and a number of things do not appear to add up. 

In 1964 the SR General Manager set up a committee Z5 to determine a future traction policy for the Isle of Wight. When the CM&EE department looked at the performance of the proposed MLV, with the proposed train formation, they found that to meet the timetable two MLVs per train would have been needed. This wrecked the economic case for using these vehicles.

The JA Class 73 had already been in service 2 years prior to 1964 and had been in a constant change design stage since possibly before 1950....by 1958 they had more or less finalised  the design and orders were placed in 1959..which is 5 years before the 1964 Z5 committee proposal on the IoW.

 

Also both the MLV and class 73 design would have been too tall for the Ryde Tunnel regardless of body width...

[bécasse]

I would be interested to see the evidence of your theory above. Your post has been discussed on the SeMG email group and a number of things do not appear to add up. 

In 1964 the SR General Manager set up a committee Z5 to determine a future traction policy for the Isle of Wight. When the CM&EE department looked at the performance of the proposed MLV, with the proposed train formation, they found that to meet the timetable two MLVs per train would have been needed. This wrecked the economic case for using these vehicles.

The JA Class 73 had already been in service 2 years prior to 1964 and had been in a constant change design stage since possibly before 1950....by 1958 they had more or less finalised  the design and orders were placed in 1959..which is 5 years before the 1964 Z5 committee proposal on the IoW.

 

Also both the MLV and class 73 design would have been too tall for the Ryde Tunnel regardless of body width...

 

My information came from the mouth of  the late Ray Chorley who was working in the Eastleigh drawing office at the time, although I can't remember at this juncture whether he had worked personally on that particular scheme or just taken an interest in the work of others.

 

 

I seem to recollect being told that the scheme was killed not just by the need to work summer Ryde line trains with a loco at each end (which I believe is what was suggested) but because it highlighted the need to replace the rolling stock as well. I suspect that it was intended to work the Cowes line all-year and the Ventnor line in winter on a push-pull basis but I can't now remember whether we discussed this at the time. My recollection is that the IoW MLV proposal was originally worked on almost concurrently with the initial Hastings diesel scheme, the similarities are obvious, and I have a feeling that Ray may well have moved to Derby by 1964 anyway. BR schemes had a habit of resurrecting themselves and, indeed, it would have been wrong not have reconsidered the idea when something had to be done in the mid-1960s.

 

Finally, are you sure that an ED wouldn't have got through Ryde Esplanade tunnel as it existed in the early 1960s, don't forget that the track was raised considerably as part of the electrification works to reduce the risks of flooding.

[bécasse]

Thinking it through more thoroughly, the conversation with Ray Chorley was no later than The Model Railway Club's Easter exhibition in late April 1962 and quite possibly a month or two earlier, so it definitely didn't relate to any 1964 proposal.

 

Most afternoons I used to catch the 3.52pm down Orpington from West Dulwich on my way home from school. Just before that time there used to be an up Ramsgate-Stewarts Lane test train path (head code 16) which was regularly used to "try out" the SR's latest toy, so I would have been one of the first to see an ED in action on one of these test trains in the spring of 1962. The window arrangement along the side of the ED (a JA, of course) puzzled me and so I asked Ray Chorley about it. This may have been one Thursday evening at Keen House where both he and I were irregular attenders at the time or it may have been at Central Hall, but that was when Ray said that it was a hangover from the IoW MLV proposal with fenestrated double luggage doors, the doors having gone but the windows retained (and note that the window arrangement wasn't perpetuated in this form on the JBs). I have a feeling that Alan Blackburn may have been a party to the conversation but I can't be at all certain on that over half a century later.

 

Incidentally, the oddest test train of all didn't involve an ED but a 4CEP+MLV formation hauling a train of fitted 16ton mineral wagons, easily replicated in model form these days - convincing spectators at an exhibition that it really happened might be more difficult!

[Andy Y]

However, he repeats the old myth that 

 

Has anyone else tendered that it's a myth?

[zephyrman]

Just remember the tunnel was only lowered in 1967 as steam trains were still using the tunnel.

 

However Brian Hardy also mentions the same in Underground number 11.

 

No smoke without fire.

 

 

Also Brighton and Eastleigh produced drawing for the convertion of 84xxx tanks. We have them at Havenstreet.

 

Interesting as the mods were deliberately over engineered. One would say to make it to costly on purpose.

 

Replacement for 02's started in the late 1950's not the 60's

[slilley]

Just remember the tunnel was only lowered in 1967 as steam trains were still using the tunnel.

 

However Brian Hardy also mentions the same in Underground number 11.

 

No smoke without fire.

 

 

Also Brighton and Eastleigh produced drawing for the convertion of 84xxx tanks. We have them at Havenstreet.

 

Interesting as the mods were deliberately over engineered. One would say to make it to costly on purpose.

 

Replacement for 02's started in the late 1950's not the 60's

 

 

The design work for the 73s was done at Brighton. The drawing register for the time is at the NRM. I have copied large chunks of it for my research work on the 71s and 74s which of course overlaps with the 73s both the JA and JB variety.

 

I would be interested to see the evidence of your theory above. Your post has been discussed on the SeMG email group and a number of things do not appear to add up. 

In 1964 the SR General Manager set up a committee Z5 to determine a future traction policy for the Isle of Wight. When the CM&EE department looked at the performance of the proposed MLV, with the proposed train formation, they found that to meet the timetable two MLVs per train would have been needed. This wrecked the economic case for using these vehicles.

The JA Class 73 had already been in service 2 years prior to 1964 and had been in a constant change design stage since possibly before 1950....by 1958 they had more or less finalised  the design and orders were placed in 1959..which is 5 years before the 1964 Z5 committee proposal on the IoW.

 

Also both the MLV and class 73 design would have been too tall for the Ryde Tunnel regardless of body width...

 

The design work for the 73s was done at Brighton. The drawing register for the time survives at the NRM and i have copied much of it for my research on the Class 71s and 74s whose design  work was also done at Brighton. The earliest drawing I can find for any electro-diesel is dated 14/07/1959. Though I admit I only have from 1956 onwards.

 

For much of the time previous to that the drawing office had been working flat out on the 71s.

 

Regards

 

Simon

 

Simon

[Southernman46]

Regardless - it all still resulted in the most useful locomotive class ever built ......................