NSWGR Proposed "Mini Railmotor"

 
  NSWGR_C3813 Locomotive Fireman

Location: Banned (beware of cringy posts from 4 years ago)
When I was looking at the workshop plans for Diesel and Electric Locomotives I came across these two "Mini Railmotor" plans.

Does anyone know about these proposed carriages?

All I know is that they bear a resemblance to the 900 class and they are small two car sets. The second one appears to have to have a six - wheeled articulated bogie between the two cars whereas the first has two four wheeled ones.

What was the intended for and why was it cancelled?

To find them see pages 43 and 44 of the link inserted below.

http://coalstonewcastle.com.au/plan/008/document/

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  Junction box Chief Commissioner

Location: newy
Looks like prototype 620 drawings which became light weight rail motors for the state
  M636C Minister for Railways

When I was looking at the workshop plans for Diesel and Electric Locomotives I came across these two "Mini Railmotor" plans.

Does anyone know about these proposed carriages?

All I know is that they bear a resemblance to the 900 class and they are small two car sets. The second one appears to have to have a six - wheeled articulated bogie between the two cars whereas the first has two four wheeled ones.

What was the intended for and why was it cancelled?

To find them see pages 43 and 44 of the link inserted below.

http://coalstonewcastle.com.au/plan/008/document/
NSWGR_C3813
These are not rail motors but are locomotives.

They are related to the drawing immediately following, the cab unit with cardan shaft drive from four body mounted traction motors. This was intended to be equivalent to the SAR 900 class, fitted with an English Electric 16 SVT engine of 1760 BHP, giving an input to the generator of about 1600 HP.

The big clue as to why this didn't go ahead can be seen in the estimated weights which were significantly less than the similarly powered SAR 900 class.

The next step was to add a seventh axle, which resulted in the unusual A1' A1A' 1A' wheel arrangement, with the engine in the left unit and the radiators, fuel and electrical gear in the right side unit. The outline of the engine is visible in the drawing of the left unit.

This probably couldn't be made to work, and yet another version, with eight axles but with two eight cylinder in-line engines in a matched pair of A1' 1A' units.

While the third version might have worked, by this time they had ordered the V-16 engines (at least, according to contemporary "Railway Transportation" magazines) and the 40 class had arrived, and proved that nothing needed to be invented.

The drawing above/before those three appears to be the AI&S 800 HP diesel electric shunter built by Comeng which used the same engine as the twin units.

The original idea was to produce a passenger locomotive for use on the North Coast line which had deteriorated badly under wartime traffic and was limited to 32 class locomotives until track repairs could be made. Trials were made with the 40 class before the end of 1952 which showed that they could do the job, but they were too valuable on freight traffic to be spared for North Coast passenger traffic.

The arrangement of traction motors on the cab unit was eventually used by GEC in the UK on the class 91 electric locomotives.

Peter
  gordon_s1942 Chief Commissioner

Location: Central Tablelands of NSW
The NSWGR Railway had lots of people drawing all sorts of things, Civil, Mechanical and Electrical and I wondered if sometimes they were given an assignment (like this power car) on a Monday morning to keep them busy and told to go away and do all the drawings by Friday morning when they were then presented to be discussed and pondered over until lunch time when they were all neatly rolled up, tied with a pink ribbon and carefully put into the next vacant pigeon hole in the event that 'One Day' they may be needed?
  GrahamH Chief Commissioner

Location: At a terminal on the www.
Interesting...
Silver City Comet revisited
Silver City Comet on steroids?
  7334 Chief Commissioner

Location: In the workshop wondering why I started 7334 in the first place
Ron Preston's book "The Green Diesels" makes reference to some of these proposals in Chapter 2 - The Thoroughbred. (Page 10)  If you have access to a copy it is a good read, but then Ron Preston did not write the other kind!

The "Thoroughbred" nickname allegedly stemmed from some of the designers having a liking for a punt on the gee gees.

They were a product of the mentality that the NSWGR had the skills and capability to build anything, had done so with steam locomotives, so why should a diesel be any different.

They also stemmed from the NSWGR seeking advice from the London Midland and Scottish Railway which was in the process of building the first mainline diesel locomotive in the UK.  Their advice was that the locomotive should be of 1600 HP and have 4 traction motors.  Seeking advice from the UK where there was little if any experience to draw on instead of the US where there was already a wealth of experience seems odd at this distance but that's how it was.  The SAR apparently did much the same.

At the time there was a "buy British" policy and as a result arrangements were made to purchase engines and other equipment from English Electric.  Again the SAR did the same.

One of the proposals, apparently the actual ""Thoroughbred", was the one which looked like a shortened 2 car railcar set.  It was to have the engine in one half and the auxiliaries in the other with everything connected by flexible hoses.  This was one of the problems as trying to get everything oil or water tight and keep them that way was not going to be easy.

Also the proposals envisaged mounting the traction motors on the body and driving the axles via cardan shafts.  This had the advantage that there was less unsprung mass but it meant finding space on the body for the traction motors.

In the end the NSWGR accepted that the proposed locomotives were too unconventional and fraught with potential problems and quietly decided to cancel the project.  The SAR meanwhile followed a more conventional approach and the 900 Class was the result.

Ultimately the NSWGR bought the 40 Class which were a proven design and very successful.  Then they brought themselves undone with the 41 class which were anything but.
  M636C Minister for Railways

Interesting...
Silver City Comet revisited
Silver City Comet on steroids?
GrahamH
The proposal in the collection after the shaft drive cab unit looked a lot like a six axle Silver City Comet.

It was in fact a local version of the early EMD locomotives, with two Winton 12-201A engines giving 1800 HP.

Had they bought the traction package from EMD, it might have been at least as successful as the Comet, although the 201A disappeared fairly rapidly in the early 1950s.

As to the name "Thoroughbred" I would think that the design was intended, Like the Silver City Comet, for fast running on lightly built lines. I suspect that that had as much influence on the name as a draftsmans interests. The use of body mounted traction motors with shaft drive greatly reduces vertical track forces and was adopted by British Rail for the Class 91. If you are ever in London, checking out the 91s at Kings Cross is always interesting. You can see the angled drive shafts moving inside the bogie frames at low speeds. With the new Class 800 coming they won't be there much longer.

My favourite among these is the diagram of electric 4501 with leading axles to prevent high curve forces. One wonders whether that might not have been a good idea, since that might have avoided the Granville derailment thirty years later, and it is interesting that it was considered so early. The Japanese built locomotives exactly like that, both for their own use and for use in Korea, where one of them might still exist in the North.

Peter
  NSWGR_C3813 Locomotive Fireman

Location: Banned (beware of cringy posts from 4 years ago)
Very interesting. But I think we are straying off topic. Either I'm getting confused with the State Rail Authority and the South Australian Railways. Which one are you referring to?
  M636C Minister for Railways

Very interesting. But I think we are straying off topic. Either I'm getting confused with the State Rail Authority and the South Australian Railways. Which one are you referring to?

NSWGR_C3813
I don't think there are any references to SRA, only to SAR.

The reason for the references to the SAR was that both the SAR and NSWGR intended to build locomotives using the same English Electric power unit, the 16 SVT. The articulated version of the NSWGR design was the "mini Railmotor" in the thread title.

As far as I can tell there has been nothing off topic so far.

One reason that USA designs were not considered was that the Federal Government had restricted the expenditure of US dollars while anything purchased with Sterling was not restricted.

Thus the 40 Class, built in Canada were not restricted since US dollars were not required.

Later these restrictions were relaxed and EMD equipment was imported for the GM class. B class and 42 class among others.

Peter

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