towerman
My status is now now widower
Posts: 2,968
|
Post by towerman on Jul 22, 2005 3:47:30 GMT
In the early 70's the 67TS started it's first cycle of programme lifts.For the uniniciated this is where the car body is seperated from the bogies,and bogies,brakes,shoegear and wheels are inspected and changed as required.Obviously to start this off there must be a float of replacemnt equipment.The first couple of units were done and all replacement wheels were new,by the time they started on the 3rd unit they started using the wheels from the first two units which had been turned at Acton Works.After about two or three trains had been done like this there started to be reports of a strange juddering sensation especially when braking,I was called to one train myself and can confirm it was a very strange feeling almost like the train was bouncing slightly,it was only when someone realised that the trains getting reported had recently been fitted with newly turned wheels that they got the wheel diameter guage out and lo and behold Acton had been turning the wheels out of centre.It was only fractions of an inch but instead of being circular the wheels were actually a slight elipse,no wonder they were bouncing.
|
|
|
|
Post by q8 on Jul 22, 2005 5:25:20 GMT
Oh I see. What goes round...Don't!
|
|
|
|
Post by Admin Team on Jul 22, 2005 16:03:32 GMT
Still, makes a change from the oversized 50p pieces that most trains run on though!!  |
|
|
|
Post by russe on Jul 22, 2005 17:02:52 GMT
I once saw wheels being turned at Acton Works, and was surprised at the critical 'railhead shoulder area' of the flange being turned by hand, although a tyre contour profile gauge was available for checking conformance. (Tyres are presumably CNC-turned nowadays.) I understand that some tyres are/were re-turned on a fairly regular basis - deviation from the ex-works contour being quite rapid on the Central for example, with its nasty curves between White City/Shepherds Bush and Bank/Liverpool Street. The concentricity and roundness of the ones I saw were excellent, and the turner told me that the prime cause of rough running on the Central was wear and slop in the bogie pins as much as worn wheel contours.
Russ
|
|
|
|
Post by q8 on Jul 22, 2005 17:26:01 GMT
After stock in the old days came back ex-Acton Works they had generally re-profiled wheelsets under them. This used to caused terrible screeching at Bow Road and Monument until they wore to the "norm"
By-the-way ANY train ex-works at Acton was GUARANTEED to have a defect on it.
|
|
