4474

I appreciate that this reply is rather late in the day but I have only just come across this post. The train referred to in the previous posts is in fact the North - Eastern Region's train. It sprayed the Scottish Region as well as the NE Region during the time I was involved with it between 1964 and 1967. I have a number of photos which I would be happy to pass on if they are of use. In the meantime here are two photos to give you an idea

Greetings Use these pictures as you wish, I do have more which I will post as I find them, scan them and restore them. 4474

The photos show the BT11 solebar end casting upside down on the marking-off table at K & L Steelfounders at Letchworth on 9th April 1976. The design of this casting was the most difficult task I had on the project. It was drawn full size and took 11 A0 sheets to show the amount of detail necessary to define it. We always had problems finding enough space on APT but here it was more limited than usual in that the top of the casting had to be kept clear of the airspring when the body tilted and the position of the bottom of the casting was determined by the location of the top of the primary spring. This meant that the walls of the casting had to be thick to give the necessary strength. This in turn meant that the cores that made the casting hollow needed a lot of support to withstand the flow of molten metal. The non-circular holes are for the core support and the circular holes are to accommodate the yaw damper. The core support holes were filled by plates welded in later. The degree of technical and delivery risk on this casting was such that the order was split between two foundries even though it meant paying for two sets of patterns. The other foundry was in Leven in Fife so it meant some long journeys

Two points about the pantograph anti-tilt mechanism. Firstly, when the power car was not tilting the pantograph tracked the wire more accurately than a conventional loco because when the body moved laterally the pantograph rocked in the opposite direction cancelling out some of the sideways movement between pan. head and wire. Contrast this with the roof-mounted pantograph on a conventional loco. The pantograph moved laterally the same distance as the body and if the body rolled the pantograph moved further still relative to the wire. Secondly the vertical holes through the body that accommodated the stabilising rods were used as ducts through which cooling air for the traction motors could be drawn. This was a fortunate by-product of the design because it simplified the problem of how to get cooling air into the traction motors at four locations. As with several areas, air management in the power car was a new problem for loco designers as all previous locos had the traction motors on the bogies.

Sometimes a long shot finds its mark. I worked on the APT project for 11 years and was heavily involved with the design of trailer bogies, friction brakes and pantograph anti-tilt mechanism. I'd be happy to come along some time and talk APT. Is there a way I can contact you outwith this forum to discuss arrangements?

Click on this link and look at the first photo thereon https://en.wikipedia.org/wiki/LNER_Gresley_Classes_A1_and_A3 Regards, Mike

I had little to do with E train when working in the APT project group but I did have a ride on PoP train (note the lower case 'o' as it was usually written this way). What I remember most is the noise level in the unfurnished, all metal cabin. When going over a rail joint it wasn't far off threshold of pain level. The floor was partly metal mesh so that the bogie could be observed in flight as it were and if you had seen the way it leapt around you would have been very wary about getting on a train again. I think by this time the original swinging arm trailer bogie as shown on the various photos connected with this topic had been replaced by an H3X bogie, the prototype of the BT11 used on APT-P. Perhaps someone could confirm this.

Hello Chris, There were no engineering problems in increasing the ride height, it was simply a case of avoiding the work involved in changing the drawings. It was the practice in the APT project group to put what were called reference dimensions on the assembly drawings, for example the height of the top of the airsprings above rail level which was 1150mm. These dimensions were fundamental to the design but not to the manufacture which is why on the working drawings they were shown in brackets thus (1150). Putting it another way, the various components that influenced the ride height had to be designed and manufactured so that if they were all made to their nominal dimensions the actual ride height would be equal to the height denoted by the reference dimension. There were no compromises on this. The reference dimensions were so important that they had to be the same on every drawing where they appeared and they appeared on a good many drawings. The drawing office was always under pressure to produce the manufacturing drawings so any work that could be postponed or avoided was always postponed or avoided. Hope this helps

Re ARC's post of 13th March 2013 about the wheel diameter on the trailer bogies, as I was the engineer who supervised the preparation of the manufacturing drawings I can tell him that the wheel diameter was 783.5mm. The reason for this peculiar dimension was that it was originally intended that they should be 785mm but, and here memory is slightly hazy as it was 38 years ago, we needed to put an insulating packing under the primary springs, so to avoid raising the height of the train and more importantly, to avoid the work involved in changing a number of drawings, it was easier to change the wheel diameter and sort the problems out at the series production stage (which never came). BTW the power bogie wheel diameter was 864 mm . Hope this is of interest.