sharp curves + effect on wheels

[Old Timer]

but if the flange does not contact the railhead on a normal basis, why does enough wear and tear occur on this flange to the extent that there are such preventative measures on the sharp curves?

All track geometry is a compromise, either to allow different types of train or allow differential speeds.

In an ideal world we would cant track to the correct degree assuming that every train will enter the curve at the same speed. Unfortunately this is rarely the case and we have to take into consideration both freight and stopping/starting/slower passenger trains.

The outcome is that the curve design is a compromise based on the best solution for all trains.

This means that fast trains will run against the high rail, whilst slow trains may run on the low rail.

Very rarely can we achieve the optimal solution.

 

[Capybara]

Any more shouts for the sharpest curve on the network, then? The one at the south end of the Crimple viaduct near Harrogate is a real screecher.

 

[Hydro]

Um - hate to differ and all that but the Branch is quite s-shaped - from Brockenhurst the major curves are L-R-L-R-R-L-L-R. I'd have thought (but would love to be corrected ) that wheel wear would pretty well even out. I always thought the turning trips were to even out wear on the doors as all platforms are on the same side.

Just what I've been told. Still thinking about it, the train does go there and back, for every journey taking those curves, it comes back and does them in reverse, possibly evening out the wear. Maybe the turning trips are just to give the drivers a change of scenery


Sharpest curve? Maybe not *the* sharpest, but the curve coming out of Dover Priory towards Folkestone is nasty.

 

[chuffchuff]

Sharpest I know is London Bridge, Cannon St and Met Jn

 

[bluebottle]

The curve at Poole's quite sharp. Makes for fun minding the gap on 450s going west and 444s going east

 

[boing_uk]

Coming out of Platform 6 at Blackpool North, there is a reverse curve within the pointwork where the P6 track joins the track to P8, then the track to P5&4; the former curving to the right and the latter curving to the left.

There is a considerable jolt as the train crosses through this and you can feel the almost sideways movement of the vehicle as each bogie moves in an entirely different lateral direction.

What I mean by that is that by the time the front bogie is moving through the pointwork from P4 and starting to bear left, the rear bogie is coming through the pointwork from P6 and is just starting to kick right.

 

[A60K]

Not on the national network I know, but the Delta Junction at West India Quay on the DLR is very sharp - around 100ft radius I think, from what I was told on a visit years ago.

OT's point about uneven wheel wear is demonstrated by how, before the recent change in service pattern, occasional Circle Line trains on LU were sent off to Whitechapel to stop them going round continually in a circle and causing uneven wear.

Wasn't there a problem recently with the 139s on the Stourbridge branch having uneven wheel wear? I'm sure I remember reading that a turning triangle or turntable was being considered to solve it. The conventional DMUs didn't suffer the problem because they weren't confined to the branch as the 139s are.

 

[truckman060473]

section of line not for public use at end of the Stenaline station at Fishguard which turns 90 degrees and extends out to a jetty has what looks like an extreme curve. a sign there (or was there many years ago) read; "class 35, 37, 47, 52 engines prohibited beyond this point." this may or may not be to do with the curve being too sharp for those locos. not sure

 

[red circle]

I probably need another OT memory jolt on this one but we used to knock a couple of wagons into a yard just west of Stratford on the UE side,yard was surrounded by a pallisade fence with gates (gas board?).Out side the gates was a pile of sawn off Instanter centre links,the shunter had to unhook all the wagons to be shunted in and hang these links between both wagon couplings,this doubled the coupling length and prevented buffer lock.

 

[TheSlash]

Hydro is correct about the Lymington branch problem. I believe it's the curve between Brockenhurst and Ampress works halt or whatever it's called

 

[MrC]

I believe it's the curve between Brockenhurst and Ampress works halt or whatever it's called

Don't think so - if you look at Google Earth you can see that the branch isn't one big curve at all but a whole series of reverse curves which pretty well even out.

Next time I see a fleet bod I'll try and get a definitive statement.