HST coach bogie

[truckman060473]

what are these cylindrical rods on HST coach bogies? and did they exist before the refurbs. i can't recall noticing them in previous years

 

[CallySleeperKid]

Always wanted to know that myself!

 

[Kingfisher200262]

That's the traction rod. You can see it here, on the BT10 bogie diagram.

 

[truckman060473]

so it has something to do with the wheel's traction during braking?????
--- old post above --- --- new post below ---
looking at it again could it be to reduce side play of the sprung axle which is pivoted?

 

[Kingfisher200262]

The traction rod between the bogie frame and the axle box provides the longitudinal control of the wheel set.

The stiffness of the traction rod determines the extent to which the wheel set is able to steer in curves, so the traction rod characteristics can be changed to "tune" the bogie during initial on-track testing of a new bogie design.

 

[ralphwedgewood]

It attaches the swing bolster to the bogie frame. You can see the same sort of thing on B4 and Commonwealth bogies.
On older types of bogie i.e. Gresley Spencer Moulton, the swing bolster is supported front and rear by a slot in the bogie frame, so the bolster can move sideways but not forward or back.
I don’t think that it is generally realized that the better types of older bogie (Gresley and Great Western 9ft) had compound bolsters with an inner bolster swinging under an outer bolster which in turn swings under the bogie frame – complicated? You bet!
Little wonder that British Railways were in such a hurry to come up with something less complicated and far easier to maintain – the B4/B5 family. A problem in this country is that the tight loading gauge associated with high platforms means that the swing links, which determine how far the coach body can move laterally are limited in length in comparison with those found under continental rolling stock.
Which is why trains in Europe often seem to ride better than ours.
One last thing – what if coaches didn’t have swing bolsters at all? Well, the natural motion of a four wheel truck with conical tyres is S shaped along the line of route, so above a certain speed the coach would be shaking from side to side – there is (was) a good demonstration of this phenomena in the London Science Museum.

 

[truckman060473]

It attaches the swing bolster to the bogie frame. You can see the same sort of thing on B4 and Commonwealth bogies.
On older types of bogie i.e. Gresley Spencer Moulton, the swing bolster is supported front and rear by a slot in the bogie frame, so the bolster can move sideways but not forward or back.
I don’t think that it is generally realized that the better types of older bogie (Gresley and Great Western 9ft) had compound bolsters with an inner bolster swinging under an outer bolster which in turn swings under the bogie frame – complicated? You bet!
Little wonder that British Railways were in such a hurry to come up with something less complicated and far easier to maintain – the B4/B5 family. A problem in this country is that the tight loading gauge associated with high platforms means that the swing links, which determine how far the coach body can move laterally are limited in length in comparison with those found under continental rolling stock.
Which is why trains in Europe often seem to ride better than ours.
One last thing – what if coaches didn’t have swing bolsters at all? Well, the natural motion of a four wheel truck with conical tyres is S shaped along the line of route, so above a certain speed the coach would be shaking from side to side – there is (was) a good demonstration of this phenomena in the London Science Museum.

very nice bit of info. did the original HST 125's have them, or is this a bogie improvement? Recently the cl. 43 power cars also seem to have some sort of damper between the bogie and body like the class 175's

 

[royaloak]

They always had the traction rod, if they didnt the bogie would slop back and forward.

The power cars have always had the damper, it is normally covered in muck so is easy to miss.

 

[ChrisCooper]

That's probably the thing, these sort of bits are often far more noticable on new or refurbished trains as they will be cleaner and might even be painted, so will stand out against the same equipment on a train that's been in service for a long time and everything is covered in dirt.

 

[TGV]

AKA Yaw Damper. That's what we called them at E* because they were actually dampers on 373's, not just a rod - see pic of trailer bogies here as an example:

http://rhaworth.me/06pa/063329.jpg

It's been said - they control the yaw motion of the bogie frame relative to the train body, which sorts out oscillations and helps changes of direction to keep smooth.

 

[rail-britain]

All BT10 bogies have the horizontal rod, classified as the Traction Rod (part 3.4.6) but more commonly known as a Yaw Damper

The photograph shows a BT10A bogie with "Short Swing Links"
These have to be used on sections of track with 3rd rail
The other type is "Long Swing Link" and that is the type shown in the picture, see part 3.4.7
As you can see, this part is also referred to be the wrong name!
However, it was easier to identify as SSL and LSL rather than SPSL and SPSR (long and short versus loop and rope)

 

[royaloak]

The long swing links have been changed from the metal stirrup (as in the diagram) to a metal rope sling (same as short SL) but the attachment on the bogie is a different shape and angle.

 

[rail-britain]

The long swing links have been changed from the metal stirrup (as in the diagram) to a metal rope sling (same as short SL) but the attachment on the bogie is a different shape and angle

There are still some of the original "metal stirrup" in use, at least three coaches on an East Coast HST today

 

[royaloak]

Will have to keep an eye out when up that way.

 

[Kingfisher200262]

There are still some of the original "metal stirrup" in use, at least three coaches on an East Coast HST today

There is no issue with Long Swing Link vehicles operating on the ECML. The wire rope version of the swing link is an improved design from the original stirrup.

The main issue is that BT10 bogies that are fitted with Long Swing Links are prohibited from operating on third rail lines, as there is a risk that the swing link may foul the third rail.

The vehicles that are fitted with one or more Long Swing Link bogies have the letters LSL painted on the body end, below the main data panel.

 

[royaloak]

Are the LSL bogies modified with the wire rope sling still barred from the SR though?
I notice they are still marked as LSL on the ends!

 

[rail-britain]

There is no issue with Long Swing Link vehicles operating on the ECML. The wire rope version of the swing link is an improved design from the original stirrup.

The main issue is that BT10 bogies that are fitted with Long Swing Links are prohibited from operating on third rail lines, as there is a risk that the swing link may foul the third rail.

The vehicles that are fitted with one or more Long Swing Link bogies have the letters LSL painted on the body end, below the main data panel.

Yes, I am aware of the LSL lettering
This was an issue in BR (Intercity) days as quite often trailers could be swapped at Craigentinny from an East Coast set to a Cross Country set
Obviously that doesn't happen now, so its not a major issue
When I worked on Intercity East Coast it was basic knowledge to know about the bogies and to recognise a "correctly" operating one, so that a faulty one if seen could be reported
I used to also have a list of which East Coast Mark 3 trailers had SSL or LSL, as well as some of the other minor variations between them

I remember working on one set where the bogie on one trailer had been reported as having a knocking noise as it was travelling northbound
The bogie was examined at Edinburgh but nothing wrong could found
Shortly after departure from Stonehaven several passengers reported there had been a banging noise along the side of the train (which was quite common on HST when they lift loose ballast)
On arrival in Aberdeen I had another look at the bogie, several components were now missing, with lovely clean metal edges where the rest of the bogie was dirty!
The coach was taken out of the set and dumped in Aberdeen for three days for repair, the same set came back and the coach was reinserted (ironically making it temporarily into a 9 coach set)

 

[bluebottle]

Are there any Mark 3s operating over third rail lines at the mo? I can't think of anywhere it happens.

 

[rail-britain]

Are there any Mark 3s operating over third rail lines at the mo? I can't think of anywhere it happens

There shouldn't be, but there is a possibility with diversions on Cross Country, FGW, East Coast, and Grand Central
It is also possible the Network Rail HST may have to operate over some sections of track with a 3rd rail, so this is the most likely

 

[CarterUSM]

Does the caledonian sleeper not travel over DC lines in the watford area?