Transponder or Pantograph?

[The Stationmaster]

11 hours ago, Trog said:

 

Try keeping your stressing up to date, ensuring that your breather switches are properly adjusted, maintaining the proper raised ballast shoulder, ensuring that your pads clips and nylons are in good condition so the rail can not move longitudinally, lubricating and adjusting fish plated rail joints, fitting LREPs to tight curves and the switch panels of S&C on timber, that sort of basic house keeping. Going a bit further by removing un-necessary trigger points from the track, such as where failed concrete sleepers have been replaced by odd timbers, or wet spots where the track pumps so reducing the contact area between sleeper and ballast. Painting the rails should be un-necessary* for properly maintained track.

 

* An exception to this is perhaps switches, particularly the blades of switch diamonds which are due to their design are susceptible to heat related expansion problems. But if you see long lengths of plain line in particular painted white, you know that the local maintainers are either under staffed and desperate or sub competent.

Your comment about lubricated and adjusted fishplated joints is very pertinent to a discussion the other evening about the track on our branch.  Somebody asked when a particular stretch of jointed track, through a village, was going to be replaced by  cwr because it was very noisy and stated it was receiving no maintenance.  That latter point was wrong to the extent that lot of spot resleepering has being going on for some months however the noise being described had a bit of further discussion and it was clear that what was being talked about were dipped joints.

 

Judging by the frequency with which the mobile gang visits Tesco for 'supplies' they are about on the branch reasonably often but there is little or no indication that fishplates have been oiled and I suspect there hasn't been anything a bit more complicated than that such as rail end trimming.  Trains are all dmu so rail loadings and all the ballast is in good condition with no signs of pumping anywhere but I do get the impression that joint maintenance is not being done in the old fashioned way or to that standard.

[Reorte]

On 26/07/2019 at 10:30, Pacific231G said:

Interesting Brian. How many problems have they had in the exceptionally hot weather. Do SNCF paint their rails white? NR were being criticised for this on twitter this  morning as if it was a desperate stop-gap rather than the sensible measure that any halfway competent engineer knows it to be.

 

There's a depressingly common line of thinking that if something isn't a ludicrously high-tech solution you can apply once and forget about (that it'll be redundant in five years being beside the point) then it's a desperate bodge. How can a tin of paint possibly be a sensible approach when we'e got a load of technology lying around?

[The Stationmaster]

7 hours ago, Reorte said:

 

There's a depressingly common line of thinking that if something isn't a ludicrously high-tech solution you can apply once and forget about (that it'll be redundant in five years being beside the point) then it's a desperate bodge. How can a tin of paint possibly be a sensible approach when we'e got a load of technology lying around?

But the interesting thing is that it has now been going on for 25 years to my direct knowledge although it's use initially was pretty limited.  The fact that it has spread (I'm talking about its use on pointwork) might indicate that it has been found effective?

[jim.snowdon]

7 hours ago, The Stationmaster said:

But the interesting thing is that it has now been going on for 25 years to my direct knowledge although it's use initially was pretty limited.  The fact that it has spread (I'm talking about its use on pointwork) might indicate that it has been found effective?

It is. It's one of those remedies that is simple and effective, and none the worse for being a low-tech solution.

 

Even on the miniature railway I help look after, the colour of the rail, ie clean(ish) aluminium or dirty can make a substantial difference in the rail temperature on a high sunshine day - the difference between "that's warm" and "ouch, that's hot". It may be smaller, but the Laws of Physics are still the same.

 

Jim

[Gordon H]

On ‎26‎/‎07‎/‎2019 at 22:48, Pacific231G said:

In its original form the railway pantograph does sort of vaguely resembles the drawing device (if you don't  look too closely) in that it is a parallelogram but you need the externally extended arm that railway pans. dont have to actually reproduce a shape. However, the word's been used  well beyond its original meaning. Such is the English language.

 

 

Surely the drawing board pantograph comparison refers to the fact that on a drawing board it keeps the ruler at the end of the moving arm parallel to the board edge at all times. The railway pantograph does a similar job by keeping its head parallel to its base throughout the allowable range of movement - hence the linkages employed.

[Bucoops]

Pantograph = Current Collection Device. Or occasionally a wire collecting device when it all goes wrong.

[Reorte]

On 28/07/2019 at 01:28, The Stationmaster said:

But the interesting thing is that it has now been going on for 25 years to my direct knowledge although it's use initially was pretty limited.  The fact that it has spread (I'm talking about its use on pointwork) might indicate that it has been found effective?

 

That's my point. Simple and effective but leaves some people rolling their eyes ("resorting to crude, primitive methods"), apparently for not being high tech enough. Judging by the stretch near where I used to live it needs redoing every year though. Interestingly it only gets applied to one track, which is steel sleepered. The other, with concrete sleepers, gets left unpainted.

[Trog]

2 hours ago, Reorte said:

 

That's my point. Simple and effective but leaves some people rolling their eyes ("resorting to crude, primitive methods"), apparently for not being high tech enough. Judging by the stretch near where I used to live it needs redoing every year though. Interestingly it only gets applied to one track, which is steel sleepered. The other, with concrete sleepers, gets left unpainted.

 

There are two main types of steel sleeper spade ended where the end of the sleeper is turned down into the ballast, and the older crimp ended type. Crimp ended steel sleepers have less end area and hence give less resistance to buckling, so heat precautions such as speed restrictions and inspections kick in at a lower temperature. This may be the driver for using the paint to keep the rail temperature down by a few degrees.

 

The reason using white paint is becoming more common could also be due to a decline in the level of heat resistance preparation due say to lack of manpower, as much as it being a wonderful easy way of keeping the rail temperature down. Because except in the most extreme weather with a few exceptions, properly maintained track should not need to be painted. As it is designed to cope with the stresses generated by the heat.

[caradoc]

Many of the switches in the 'jungle' outside Glasgow Central have white-painted rails, to reduce the likelihood of points failures; In an ideal world they would be adjusted to take account of temperature variations, but the number of point ends at Central, plus the fact that train movements only cease for around 4 hours each night, probably make this impractical. And summer temperatures, even in Scotland, can vary wildly; Last Thursday, for example, it was shorts and T-shirts weather, by the weekend sweaters were required !

[Supaned]

On 26/07/2019 at 20:12, Trog said:

A modern transponder as used by Pendolinos etc. note how fragile and cheap looking it is compared to the BR equivalent. Not much chance of that still working after you have run a couple of JCBs over it.

 

Err. That's a TASS Balise (and yes , that it what it is called) , which has stored data used to determine the Tilt Authority and Speed Supervision (TASS) for Classes 221 and 390 to use tilt operation

Edited July 30, 2019 by Supaned

[BernardTPM]

A TASS Balise is still a transponder though, like a Ford Fiesta is still a car.

[Pacific231G]

On 29/07/2019 at 12:39, Gordon H said:

 

Surely the drawing board pantograph comparison refers to the fact that on a drawing board it keeps the ruler at the end of the moving arm parallel to the board edge at all times. The railway pantograph does a similar job by keeping its head parallel to its base throughout the allowable range of movement - hence the linkages employed.

I was comparing it with the device used for copying and scaling drawings invented by Christoph Scheiner in 1603

not with the very useful drawing board device (a great advance on the Tee Square) 

 

I think the drawing board pantograph is yet another example of a mechanism that vaguely resembles a pantograph in its original meaning and has acqured the same name; just as happened with current collecting pantographs on railways .

It is in the nature of a living language that words acquire new meanings through usage, often because something bears a vague resemblance to something of that name.  Did the headlamps of early locomotives bear a vague resemblance to the lamp carried on the head of a miner? What, apart from its name, does a semaphore signal have in common with a French military telegraph? 

 

 

It's not just in English. Somebody on France's railways decided that this AWS/ATC ramp  looked like a crocodile  so that's now its official name. 

 

Edited July 30, 2019 by Pacific231G