Over-enthusiasm with the wheel lathe causes Metropolitan line safety inspections and severe disruption

[Wickham Green too]

If it's going to take six weeks to sort out, it must have been more than several. 

[New Haven Neil]

This is as bad as the guy that suggested using EM wheel standards on P4 track in MRJ - heads will roll!

[corneliuslundie]

They obviously need to start getting their wheels from a reputable company such as Slaters.

Jonathan

[Grovenor]

15 hours ago, rab said:

From the BBC piece in the OP:

 

According to a bulletin send to staff, Metropolitan line users

will now face six weeks of a reduced service.

Somehow the equipment that turns the wheels for some

of the trains has caused defects in the wheels.

And the next sentence with the 'too small' reference is

Quote

One source told me the wheels were now slightly too small.

Hence hearsay as I said, not 'official info'.

[Nearholmer]

Hexagon’s suggestion of incorrect profile is far more likely, and it has happened before on LU. My memory is dim, and I’m not a RS engineer, but in the 27 years I worked there on other sorts of engineering certainly one fleet went through this sort of problem.

 

IIRC, Met stock runs to a national network profile, which is different from the profile(s?) used on tube lines. And no, I don’t know how things work on lines where both met and tube stock run, or where tube stock runs over national infrastructure.

 

I might see a man who knows later, but my dim memory tells me that tube profile has steeper coning angle to cope with tighter curves and generally very dry, high friction, railhead.

 

Of course, if it is a profile problem, it may not be that the wrong one has been selected; it could be that the lathe has gone out of tolerance and has cut a profile that matches no standard at all, or is permitting too great a difference between dimensions on wheels on the same axle.

 

 

 

 

Edited April 14, 2022 by Nearholmer

[rab]

8 hours ago, Grovenor said:

And the next sentence with the 'too small' reference is

Hence hearsay as I said, not 'official info'.

As you will