Flange-bearing crossings speed restrictions

 
  route14 Chief Commissioner

Melbourne trams' speed limit through points and crossings is 15 km/h regardless of the direction of travel.  However you will actually see trams traveling through those track components in the straight direction at higher speeds.  It is even approved by some trainers that it is OK to take the straight at 30 km/h, although not supported by any written rule.

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  RTT_Rules The Ghost of George Stephenson

Location: Dubai UAE
Feedback from Stockholm is 20km/h on straight through in city.
  woodford Chief Commissioner

Do we have flange bearing turnouts in Melbourne?
There are, or used to be, flange running crossovers in the 90 degree crossings in the city. These were intended to reduce impacts and resultant noise but I don't know if they are still used.
If they are still used they are ineffective as trams still seem to crash through these crossovers.
I have been told that a lot of Melbourne's crossings are flange bearing, however that was information I received from a contact at the LXRA. Yarra Trams themselves are very hard to get a response from.

Yarra Trams standards state 15kph speed restrictions apply to the diverging move at turnouts, but no information about the straight move.
Prue
You may try an get in touch the manager of external projects at Puffing Billy (It used to be John Shaw that was some time ago). They did the track for the tram at Portland (Victoria, Australia). They had to get the frogs for the switching cast in steel. I am sure if John is still there there would be little he did not know about them. He was still there last year.

PB's external project groups last year was rebuilding some of the trestles on the Cudgewa line for the rail trail.

woodford
  justapassenger Chief Commissioner

Usually you only see a short arm boom on a pedestrian track crossing but that one may be the official footpath or Cycle way, hence the boom.
Looking behind the boom there does appear to be some other formed traffic ways.
I must say I cannot understand why they made the crossing as it is because of the impact the wheel must get when it hits that cross rail.
gordon_s1942
The mini boom is for the footpath, and is nothing more than safety theatre.

I found the location on Google Maps, and a look on Street View (images just a few months old) shows that there's quite a lot going on there, with there also being a street that crosses the road and another mini boom on one of the footpaths. Have a look off to one side and you'll see a road-rail vehicle parked there and what would appear to be an old track panel from when the crossing was last relaid.

I must say I cannot understand why they made the crossing as it is because of the impact the wheel must get when it hits that cross rail.
gordon_s1942
According to the blog post linked, the railroad operator CSX introduced those crossings because they are simpler for them to maintain than frogs custom made for that crossing. It makes sense if you think about it exclusively from their point of view, the grooves worn in the freight rails by the tram wheel flanges are not ideal but a piece of straight rail is quite quite simple (i.e. cheap) to replace when the groove gets worn too deep.
  Prue Beginner

This is some very interesting stuff, thank you to the contributors.

Probably the most fascinating concept I have discovered thus far (mostly based on speculation but from many sources) :

Before the existence/wide implementation of flange-bearing designs, flange-bearing was considered undesirable and unsafe - usually caused from excessive wear or damage to the rail or wheels. Therefore, regulations were in place which classified any track that became flange-bearing as Class 1 track and speed restrictions of 10mph for freight and 15mph for passenger were implemented. Then, when flange-bearing designs became a legitimate alternative to tread bearing designs and were implemented, these restrictions were automatically applied without re-evaluation.

Since flange bearing frogs and other similar flange bearing systems are (obviously) specifically designed to flange run, sweeping restrictions like this, specific to damaged or worn components, should not have been implemented without additional analysis. It seems as though these sweeping restrictions could have carried through right to today.

I do look at many images of diamond crossings (like the ones in previous posts) and truly think they look pretty unsafe, and should probably have some sort of speed restrictions, but that doesn't justify not doing any re-evaluation. Additionally, the system I am looking at is incredibly different and it seems as though this sweeping regulation could have just been mindlessly applied just because it flange-bears. In fact, in the system I'm studying, its only partially flange-bearing and there is a check rail in place which, theoretically, should mitigate lateral forces that could lead to flange-climbing or impact on the nose-head.

Although it is speculation and impossible to prove, the thought that a regulation made yonks ago for what is, essentially, a completely different dynamic system may have been implemented on the system I'm studying without any legitimate re-evaluation is crazy to me.
  RTT_Rules The Ghost of George Stephenson

Location: Dubai UAE
This is some very interesting stuff, thank you to the contributors.

Probably the most fascinating concept I have discovered thus far (mostly based on speculation but from many sources) :

Before the existence/wide implementation of flange-bearing designs, flange-bearing was considered undesirable and unsafe - usually caused from excessive wear or damage to the rail or wheels. Therefore, regulations were in place which classified any track that became flange-bearing as Class 1 track and speed restrictions of 10mph for freight and 15mph for passenger were implemented. Then, when flange-bearing designs became a legitimate alternative to tread bearing designs and were implemented, these restrictions were automatically applied without re-evaluation.

Since flange bearing frogs and other similar flange bearing systems are (obviously) specifically designed to flange run, sweeping restrictions like this, specific to damaged or worn components, should not have been implemented without additional analysis. It seems as though these sweeping restrictions could have carried through right to today.

I do look at many images of diamond crossings (like the ones in previous posts) and truly think they look pretty unsafe, and should probably have some sort of speed restrictions, but that doesn't justify not doing any re-evaluation. Additionally, the system I am looking at is incredibly different and it seems as though this sweeping regulation could have just been mindlessly applied just because it flange-bears. In fact, in the system I'm studying, its only partially flange-bearing and there is a check rail in place which, theoretically, should mitigate lateral forces that could lead to flange-climbing or impact on the nose-head.

Although it is speculation and impossible to prove, the thought that a regulation made yonks ago for what is, essentially, a completely different dynamic system may have been implemented on the system I'm studying without any legitimate re-evaluation is crazy to me.
Prue
Prue,
I'm going to take a punt and say your client is in Aust and likely wears blue jumpers in football.

With regard to historical rules, this is Industry all over. I'm in Middle East and I can list manyof the entrenched rules my team has challenged and broken often after banging our heads against the wall for months, but eventually got through. Today's safety culture is good for not hurting people, but all too often people who cannot think hind behind it and we call them blockers. Easier to say No than think about a Yes.

Good luck and keep challenging the status quo!
  YM-Mundrabilla Minister for Railways

Location: Mundrabilla but I'd rather be in Narvik
Prue,

You may be 'but an engineering student' but by saying:

'Although it is speculation and impossible to prove, the thought that a regulation made yonks ago for what is, essentially, a completely different dynamic system may have been implemented on the system I'm studying without any legitimate re-evaluation is crazy to me.'

You are off to a bloody good start. The entire rail industry is riddled with unquestioned dargs and restrictions of all sorts.

PS: Question everything and when they wheel out 'safety' as the reason you will know that you are on to something.
  Prue Beginner

Prue,

You may be 'but an engineering student' but by saying:

'Although it is speculation and impossible to prove, the thought that a regulation made yonks ago for what is, essentially, a completely different dynamic system may have been implemented on the system I'm studying without any legitimate re-evaluation is crazy to me.'

You are off to a bloody good start. The entire rail industry is riddled with unquestioned dargs and restrictions of all sorts.

PS: Question everything and when they wheel out 'safety' as the reason you will know that you are on to something.
YM-Mundrabilla
Very excited to see how we can change some of this nonsense! Thank you!!
  tonyp Chief Commissioner

Location: Shoalhaven
Hi Prue. Thank you for posting such an interesting enquiry and sorry that you got a couple of negative responses, but this is often par for the course on an internet forum of course. Just ignore them! There are people here with lots of knowledge and you'll readily discover who they are.

Your light rail system's (Sydney?) maintenance engineer was talking bs when he suggested there is an "international standard" speed for crossing tramway points and crossings. A lot of it depends on the circumstances of individual systems, though there is a lot in common within a range.

A good best-practice system to look at is Prague which is one of the most heavily-used systems in the world (twice the level of traffic of the Melbourne system) but one where they try to maintain high average speeds while at the same time preserving the infrastructure as much as possible. They do use trams with proper swivelling bogies which makes a little difference in this case, as they are not as rough on infrastructure as the fixed-bogie trams typically used on new tram systems such as Sydney and Gold Coast, which have to be driven a little more slowly on curves and junctions. (Adelaide and Melbourne have a mixture of both types of trams.)

Somebody posted a photo above of typical flange-bearing special work in Czech Republic, a country that also supplies much, if not most of such infrastructure for Australian systems as well, so we are looking at special work from the same manufacturers when comparing both countries.

The Prague rules for crossings and points are:

10kph: on a diverging (facing) switch when turning
15kph:
- on a diverging (facing) switch when going straight
- on a merging (trailing) switch coming from a turn
- on a crossing
30kph: on a merging (trailing) switch when going straight

Here is a good video that will show you an example of the Prague operation from the driver's view. After about 11 mins into the video you will particularly see lots of junctions as the tram passes through the city centre.



https://www.youtube.com/watch?v=G6KHdyQfv5c

I hope this helps.

Edit: I'd suggest that if your operator has problems with keeping up a good average speed to maintain or improve running times, points and crossings and stops have very little to do with that.

Study the Prague video closely and you'll see that the trams accelerate very quickly to line speed and hold that as long as possible before decelerating at a stop etc. This keeps the average speed high. Our local new light rail systems have a habit of very lethargic operation and fiddly, micromanaged, constant changes in speed limits (especially in and out of stops) that disrupt the average speed.

If the inner west light rail were run as they do in Prague, given the same number of stops etc, the end to end journey would be little over 30 minutes, several minutes faster. Gold Coast light rail on the other hand performs a lot better, closer to Prague standard.
  gordon_s1942 Deputy Commissioner

Location: Central Tablelands of NSW
Accelerate very QUICKLY??? that's faster than Superman's Speeding Bullet!!!
And the braking? wow................
Could you see this being imitated here, even on its own 'Right of Way' ?  I cant.
  YM-Mundrabilla Minister for Railways

Location: Mundrabilla but I'd rather be in Narvik
Great video of Prague which has a wonderful tram network.

The YMs and I have used it several times just as a means of seeing the city and its surrounds. We have a long way to go to master the routes and cross-town lines, of course. Smile

We don't know the time/day that the video was taken but to me a number of points seem to stand out:

  • The very few road vehicles.
  • The few pedestrians.
  • The great number of turnouts and diamond crossings.
  • The prevalence of facing points.
  • The lack of traffic lights.
  • The greater distance between stops.

All of the above are directly opposed to the Melbourne system. Melbourne has a lot to learn, both philosophically and operationally.
  tonyp Chief Commissioner

Location: Shoalhaven
If a literature search is extended further, I am sure there would be a paper or papers on this in Czech Republic, where a lot of the world's technical research on modern trams and tramways is done, but at a quick glance I haven't uncovered one and my usual contacts are unavailable at the moment. However, I did come across this on prazsketramvaje.cz which is a useful site with much detailed information. It concerns the development in recent years in Prague of speed switching. The article should automatically translate depending on your browser, or you can feed it through Google Translate.

http://www.prazsketramvaje.cz/view.php?cisloclanku=2013041401

Bear in mind that an over-riding consideration in Prague is preserving the trackwork because of the intensity of tram traffic over it, something that is not as much of a factor in the much-quieter Australian operations. So speed over special work may not be as high as it potentially could be, but is compensated for in other areas of operation such as quick stop dwells and high average speeds between stops due to acceleration/deceleration and prioritisation, as mentioned before. Using trams with proper swivelling bogies also enables them to negotiate special work and trackwork generally at higher speeds because the tram does not impact the trackwork as much as the rigid-bogie trams used entirely in Sydney and Gold Coast and in part of the Melbourne and Adelaide fleets. The latter can be rough on track and special work, the higher their speed, the rougher they are.
  tonyp Chief Commissioner

Location: Shoalhaven
A little bit more from going through the technical documentation from DPP Prague, all of it on-line. This is from what may be broadly called the drivers' "road rules".

http://www.prazsketramvaje.cz/obrazky/stahuj/testy/testy_d1_2_psp_20170430.pdf

The reference to the speed on the Branik-Modrany section is the "light rail" segment shown in the opening minutes of the video posted above - at 60 km/h, faster than the allowed speed on 50 km/h on-road which is the prevailing general traffic speed limit. Here is an unedited extract that I pasted in Google Translate:

"If the tramway is not part of the road, the highest operating permit is speed 1 b.
b)
(a) 50 km / h
(b) 60 km / h
(c) 60 km / h, with the exception of the Train Station Braník - Modřany, where the higher speed is permitted
Question ID: 2587
59) The driving speed must not be more than 5 km / h: 1 b.
(c) (a) when reversing and steering from an auxiliary station
(b) when driving over a siding
(c) when handling wagons for their coupling
Question ID: 2588
60) The driving speed must not exceed 5 km / h: 1 b.
(a) when driving over a work pit
(b) when driving in the track sections on which it is operating
c) when reversing, unless higher speed is enabled
Question ID: 2589
61) The driving speed must not exceed 5 km / h: 1 b.
c) a) when driving a combined train
(b) when driving in the track sections on which it is operating
(c) when crossing the crossing point or other location of the route where the service order is set to be slow and careful ride
Question ID: 2590
62) The driving speed must not exceed 10 km / h: 1 b.
b) a) when driving over a work pit
(b) when reversing and steering from an auxiliary station
(c) when traveling over rail and overhead contact
Question ID: 2591
63) The driving speed must not exceed 10 km / h: 1 b.
(c) (a) when traveling over a point where a slow and cautious ride is set
(b) when driving against a point of the crossing point built into a straight rail branch
c) when reversing
Question ID: 2592
64) The driving speed must not exceed 10 km / h: 1 b.
(c) (a) when traveling over a point where a slow and cautious ride is set
(b) when driving through points of the crossings from the straight line
(c) when driving over the "Californien"
Question ID: 2595
65) The driving speed must not exceed 10 km / h: 1 b.
(a) (a) when driving in the track sections on which it is operating
(b) when traveling over a point where a slow and cautious ride is set
(c) when driving against a point of the crossing point built into a straight rail branch
Question ID: 2596
Test identification: p. 9 of 40 Valid from 30.04.2017
Operational Settlement System
66) The driving speed must not exceed 10 km / h: 1 b.
b) a) when towing
(b) when driving through the "Californien" [portable crossover]
c) when driving over a work pit
Question ID: 2597
67) The driving speed must not be more than 15 km / h: 1 b.
c) a) when towing
b) when driving over a work pit
c) when driving against a crossing point built into a straight rail branch, unless the signal enables higher speed
Question ID: 2598
68) The driving speed must not be more than 15 km / h: 1 b.
(a) when traveling over rail and overhead contact, unless higher speed is permitted
b) when driving over a work pit
(c) when driving through points of the crossings from the straight line
Question ID: 2599
69) Driving speed may not be higher than 15 km / h: 1 b.
(c) (a) when towing and driving on an emergency run
(b) when driving through the points of the crossings from the straight line, unless the speed signal is allowed
(c) when driving on a rails of carriages and workshops outside the halls
Question ID: 2600
70) The driving speed must not be more than 15 km / h: 1 b.
(a) (a) when driving in arcs of less than 25 m in radius, these arcs outside the enclosed labeled "Small radius arc"
b) when calling outside the stop
(c) when reversing and steering from an auxiliary station, unless the speed is enabled by the signal
Question ID: 2601
71) Driving speed may not be higher than 15 km / h: 1 b.
(b) (a) when driving on straight-point switches, unless the speed is allowed
(b) when passing through permanent and marked stops, passing the front of the train
stop marker
c) when calling up the slope outside the stop
Question ID: 2602
72) The driving speed must not exceed 15 km / h: 1 b.
(c) (a) when driving a combined train on a slope outside the stop
b) when driving in halls of depots and workshops
(c) when driving over the points of turnouts, unless the speed signal is allowed
Question ID: 2603
73) The driving speed must not exceed 30 km / h: 1 b.
(b) (a) when traveling through the points of turnouts from a branch
(b) when driving through the points of the crossings from the straight line, unless the speed signal is allowed
(c) when towing on a slope
Question ID: 2604
Test identification: p. 10 of 40 Valid from 30.04.2017
Operational Settlement System
(74) A train driver for the regular passenger transport must sign the stop at: 1 b.
(a) to arrive at such a speed as to be able to clearly identify the situation at the stop
(b) arriving at a speed of 15 km / h
(c) to arrive at such a speed as to stop without the use of the rail brake
Question ID: 2605
75) Driving speed in emergency mode: 1 b.
a) a) establishes an operational dispatching of the JPT
(b) is at an emergency speed of 15 km / h
(c) 30 km / h when driving on a slope
Question ID: 2609
76) Tramline train speed limited by the signals must be observed: 1 b.
c) a) always according to the technical condition and brake characteristics
(b) in relation to train occupancy and adhesion conditions
(c) at the latest when entering the front of the train into a section (places with limited speed)
Question ID: 2611
77) When handling railway vehicles for their connection, the driving speed must not exceed: 1 b.
(a) 5 km / h
(b) 10 km / h
(c) 15 km / h
Question ID: 2612"
  kuldalai Chief Commissioner

Another aspect that applies primarily with tramways but not on most railway applications is :

With both turnouts and crossovers the trailing leg is spring loaded to normally lie for the straight road .  So even on the straight one does nor drive over these turnouts and crossovers at high speed to give less imapct on the spring loaded return between successive pairs of wheel  sets .

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