The LNER Encyclopedia

I have been researching the 3 cylinder Stephenson link inside valve gear for the S3. Sadly, the NRM drawings register has no details that I could find, other than GAs and Pipe and Rod. There are references to common parts with the T3 (LNER Q7) that was being constructed at the same time at Darlington Works. The first of each type emerged within a month of each other in 1919. The detail I am trying to determine is the lateral and vertical arrangement to drive the middle piston valves. Fortunately T3 No. 901 is preserved and currently on display at the Head of Steam museum. In the absence of detailed drawings, is it reasonable to assume that the arrangement on the T3 (see picture) would have been the same on the S3? Regards
Richard Spoors

Hi Richard,

The NRM Darlington Locomotive Drawings List includes under drawing number 9423 the Eccentric Straps and Rods for the Class S3 which may be helpful.

Tom.

Hi Tom, yes, I had hoped so, but when I looked at them on a visit to the NRM Search Engine they were just details of the straps themselves and the angular location of the eccentric sheaves on the crank axle. I'm left with doing my best to interpret the GA. It's a pity that relatively few of the NER Darlington drawings seem to have survived for the S3.
Thanks for your reply.
Richard

Richard,

There is another collection of NER drawings, owned by the North Eastern Railway Association but placed on deposit at the Durham County Records see -
http://www.durhamrecordoffice.org.uk/ar ... mID=981008
The list has more drawings relating to the Class S3 than the NRM list and interestingly some of the drawings are described as being being common to the S3 and T3. In particular have a look at D/NERA 1/3061 which is drawing number 9297 on the Darlington Drawing List but is absent from the NRM listings.
I have a PDF of the original NERA Gateshead Loco Parts List which is the basis of the NERA collection at Durham County Records. It is easier to browse than the Durham County Records web page and I could send you a copy if you like.

Cheers,
Tom.

Although both S3 and T3 were designed at about the same time using a similar cylinder arrangement there were significant differences in the layout of the expansion links and weighshaft. On the S3 the drop links to the valve rods were in front of the motion plate whereas on the T3 these were behind it. These held the rods vertical position in relation to the expansion links

Also the centre crosshead of the S3 was on twin slidebars similar to those outside. That on the T3 had only a single slidebar.

ArthurK

Thank you Tom and Arthur for your responses. It's pleasing to note that there are one or two further drawings in existence, upon which I shall follow up through my membership of NERA.

Best wishes,

Richard

I took advantage of the list of Gateshead Works drawings and ordered some digital copies from the Durham County Records Office. I have been pleasantly surprised by service they provided. The price is very reasonable, based on the time necessary to process the drawings, and my high resolution copies were with me within a week. I can fully recommend their service.
A very happy customer!
Richard

With the help of NERA and the Durham County Records Office I have now answered my own question. When built in 1919 both the B16 and Q7 had cantilever rocking levers to drive the middle cylinder piston valves from the Stephenson link motion. In 1941 modifications were made, presumably due to wear caused by eccentric loading of the bearings and the balanced A frame arrangement shown in my photograph above was introduced to the B16/1 class. It seems reasonable to assume it was introduced to the Q7 at the same time.
I am now pleased to close this interesting research project.

Richard