Page 1 of 1
| Six problems ruining Melbourne's rail network 23/07/2015 at 13:48 #74426 | |
maxand
1637 posts |
Not to mention copper thieves. Read it here The general philosophy seems to be "If it ain't broke, don't fix it." Even though I've put it in the General category, quite a lot of the topics deal with signalling of one kind or another. I found the section on "Invisible trains" quite interesting. Hope those of you with time to read it find it interesting too. Log in to reply The following user said thank you: Gwasanaethau |
| Six problems ruining Melbourne's rail network 23/07/2015 at 16:54 #74428 | |
|
Jersey_Mike
250 posts |
What's up with those double ladders with the diamond crossovers at Richmond? Why not just use a single (or double) turnout ladder. More flexible and avoids maintenance intensive diamonds. Regarding power the capacity problems are never going to go away unless the system converts to 12 or 25kv. The Dutch have tried to modernize their 1.5k system, but the amount of amps needed to run the trains is enough to make the wires glow. Does the Melbourne suburban network contain any historic substation equipment with rotary converters or motor-generator sets? Log in to reply |
| Six problems ruining Melbourne's rail network 23/07/2015 at 21:59 #74436 | |
|
Muzer
718 posts |
I suppose the trains going invisible is actually talking about Absolute Block?
Log in to reply |
| Six problems ruining Melbourne's rail network 23/07/2015 at 22:20 #74437 | |
|
Sparky
84 posts |
" said:So what your saying is that 1500VDC traction systems will never be able to cope with the demands of suburban railway system. :doh I really beg to differ with that statement. The Sydney suburban, and for that matter the interurban network has been 1500VDC since electrification 1st occurred in 1928. Yes I agree that power demands have risen in that time but the railways have just upgraded the traction supply system to cope with the higher demand. I know there people out there saying that a 12KV or 25KV AC system is better, as with anything there are pro's & cons for both AC & DC systems and either system can handle to demands of a railway as long as it is upgraded as needed. In Sydney we have trains that draw 300-400A when accelerating and we have 100+ of these on the network at the same time every day without supply issues. Yes we have power supply failures as does any supply authority but very few are a result of the system not being able to handle the demand of the trains. " said: What's up with those double ladders with the diamond crossovers at Richmond? Why not just use a single (or double) turnout ladder. More flexible and avoids maintenance intensive diamonds.As for this comment about removing the diamond xovers. Looking at the picture in the article A ladder arrangement will simply not fit in that area. Before you go off about it will, I am referring to the fact that the last turnouts in the ladder will be on the curve at the top of picture, at that in itself will create a more maintenance intensive situation and the requirement will be to replace said turnout a lot more frequently due to curve wear. Speaking from 1st hand experience trying to maintain a FPL and detection to within the 1.6mm standards set tolerance on curved turnouts is an absolute nightmare. Some people have to remember that not everything is as easy as it seems, especially when the people writing the article are only there to sensationalise the story to sell newspapers or get viewrs I intend to live forever. So far so good Log in to reply The following user said thank you: BarryM |
| Six problems ruining Melbourne's rail network 23/07/2015 at 22:41 #74438 | |
|
Sacro
1171 posts |
" said:I suppose the trains going invisible is actually talking about Absolute Block?No, the method of working has nothing to do with the method of detection. Log in to reply |
| Six problems ruining Melbourne's rail network 23/07/2015 at 23:06 #74439 | |
Mattyq
259 posts |
" said:" said:Correct. It just means there are areas of Track Circuit Block (TCB) where train position is not indicated on any Signallers panel/workstation. It doesn't happen much anymore in Australia outside of the "Victorian" state of Victoria.I suppose the trains going invisible is actually talking about Absolute Block?No, the method of working has nothing to do with the method of detection.  Queensland hasn't had dark territory TCB in over 30 years. There was a lot of it in NSW but, as a result of the Glenbrook disaster, all auto sections are now indicated to a Signalling Centre or adjacent Signal Box, as the case may be, except a small section between Lithgow and Wallerawang which seems to have escaped the IASS project.To the best of my knowledge, there is no dark territory TCB in SA or WA. Of course, there is still plenty of dark territory in Australia but it is all within authority-based safeworking systems. Victoria, however, still has a lot of dark territory TCB, even in the suburban area (hence the derogatory phrase "Victorian by name, Victorian by nature" slogan about that state) which, funnily enough, utilises North American signalling practices. Not fat ..... fluffy!! (G Iglesias) Last edited: 23/07/2015 at 23:08 by Mattyq Log in to reply |
| Six problems ruining Melbourne's rail network 23/07/2015 at 23:14 #74440 | |
postal
5190 posts |
" said:Regarding power the capacity problems are never going to go away unless the system converts to 12 or 25kv.Once you have been shot down by your boss a few times for overstating your case, you learn to start caveating absolute statements to avoid embarassment. For example there are many systems that are sub-optimal under your analysis where the problem is actually track capacity rather than power. As a first thought, London Underground Jubilee Line running at 30 trains per hour in the peak on 630v. DC seems to negate your argument. Widening the scope, what about the whole network South of the River Thames in the UK running on 750v. DC which runs to line capacity for parts of the day. Unless you can find ways to persuade the passengers to get on and off the trains quicker you are approaching the physical limits no matter what voltage or signalling systems you are using. “In life, there is always someone out there, who won’t like you, for whatever reason, don’t let the insecurities in their lives affect yours.” – Rashida Rowe Log in to reply The following users said thank you: BarryM, TimTamToe |
| Six problems ruining Melbourne's rail network 24/07/2015 at 08:34 #74441 | |
|
maxand
1637 posts |
I hadn't come across the term "ladder junction" until now so still can't understand how it got its name, though here are a couple of links which make its structure clear: Double junction Harris Park railway station Thanks guys for your interesting feedback. Log in to reply |
| Six problems ruining Melbourne's rail network 24/07/2015 at 12:04 #74445 | |
|
Jersey_Mike
250 posts |
" said:" said:I'm going to quote the article here:Regarding power the capacity problems are never going to go away unless the system converts to 12 or 25kv.Once you have been shot down by your boss a few times for overstating your case, you learn to start caveating absolute statements to avoid embarassment. For example there are many systems that are sub-optimal under your analysis where the problem is actually track capacity rather than power. As a first thought, London Underground Jubilee Line running at 30 trains per hour in the peak on 630v. DC seems to negate your argument. Widening the scope, what about the whole network South of the River Thames in the UK running on 750v. DC which runs to line capacity for parts of the day. Unless you can find ways to persuade the passengers to get on and off the trains quicker you are approaching the physical limits no matter what voltage or signalling systems you are using. Quote: The solution is a major investment in electrical substations but the operator acknowledges this would be too expensive.So if they cannot built sufficient new substations due to the expense how do you suggest they solve their voltage drop problem without changing to a different power system? I like traditional voltages as much as anyone, but I have a friend who works with traction power systems lecture me on this point. The Dutch have been grappling with power capacity for years and currently employ auxiliary feeders along with each overhead line to combat the voltage drop. Metro-Morth and the Long Island Rail Road (750v third rail) have had a long simmering power capacity problem and use dual-mode diesels in diesel mode while in electric territory because otherwise they'd blow up the substations. When New Jersey Transit's legacy 3kv system was up for renewal in the early 1980's they leapt at the chance to go to 25k. They went from 5 substations to three, but can supply adequate voltage just using one if the others go down. " said: Due to use of a very long lens, objects in the photo are farther than they appear. Upon further review there is about 500 additional feet of tangent track available plus the option of double slip switches, which appear elsewhere in the interlocking. Just seems an odd choice for a terminal approach interlocking tend to which value maximum flexibility. Log in to reply |
| Six problems ruining Melbourne's rail network 24/07/2015 at 20:56 #74454 | |
|
Muzer
718 posts |
To be fair, I've heard of similar problems especially at the extremes of our third rail network, eg Southampton to Weymouth; and let's not forget the network-wide problems when the slamdoor units were being replaced. Though having said that, I'd suggest for a commuter network third rail is adequate, since you can likely more easily justify the expense of incremental upgrades. The problems start either when you stop doing incremental upgrades when they're needed, or when the third rail network starts to grow too far outside of commuter territory and it becomes more difficult to justify the costs of maintaining and upgrading all those substations...
Log in to reply |
| Six problems ruining Melbourne's rail network 25/07/2015 at 01:08 #74459 | |
|
Sparky
84 posts |
" said:OK there is a large expense in building new substations that MTM says is making this cost prohibitive. How could you then justify the cost to change the supply to 12kV or 25kVAC. If this suggestion was to come to fruition then surely this option would also be cost prohibitive. Not only would you be up for the cost of converting the existing/ building new AC substations but there would be massive additional costs incurred with the flow on works that WOULD need to be completed. Some of these include but are not limited to:
It is definitely not a simple or cheap task to convert a 100+yo DC system to AC. " said: I would so like to agree with you on this point, but then we would both be wrong. The picture in the article clearly shows only 2 OHW structures between the points and the TP (TP= Transition Point. Where the track commences the transition for straight track to curved track). These structures are placed no more than 35m apart. Allowing for a little bit of wriggle room for space between the points and the 1st structure and from the 2nd structure to the TP there would be no more than 90m not the 150m(500ft) that you suggested. By the time you stretch the xover out to remove the diamond xings, you will need a lot more space than the 90m you have. " said: I thought the whole premise of your argument was to reduce maintenance??? I can only assume that you have not had much experience in the maintenance of this style of track work, especially on a high use area like Melbourne. I intend to live forever. So far so good Log in to reply The following user said thank you: BarryM |
| Six problems ruining Melbourne's rail network 25/07/2015 at 22:35 #74476 | |
|
Mattyq
259 posts |
" said:" said:Most non-high speed lines in Japan are 1500v DC catenary. Trains serving the greater Tokyo area run every 2mins 30sec peak, 4mins off-peak 21hrs a day, 10 to 15 car trainsets. Most other lines around Japans more densely populated areas, same.Regarding power the capacity problems are never going to go away unless the system converts to 12 or 25kv.Once you have been shot down by your boss a few times for overstating your case, you learn to start caveating absolute statements to avoid embarassment. For example there are many systems that are sub-optimal under your analysis where the problem is actually track capacity rather than power. As a first thought, London Underground Jubilee Line running at 30 trains per hour in the peak on 630v. DC seems to negate your argument. Widening the scope, what about the whole network South of the River Thames in the UK running on 750v. DC which runs to line capacity for parts of the day. Unless you can find ways to persuade the passengers to get on and off the trains quicker you are approaching the physical limits no matter what voltage or signalling systems you are using. 1500v DC is also used in the Netherlands, Hong Kong, Ireland, Australia's 2 largest cities (Sydney & Melbourne), India (except parts of Mumbai), most of France (non-high speed), New Zealand (Wellington), the United States (Chicago Metra) and in Denmark on the suburban S-train system. Of course, this is just the 1500v DC systems. Then there's the myriad other systems around the world that run on voltages between 600v and 3000v DC. Out of all of these hundreds of networks, only a handful seem to be having issues, many of which appear to be from lack of maintenance and/or future-proofing. Not fat ..... fluffy!! (G Iglesias) Log in to reply The following user said thank you: BarryM |
| Six problems ruining Melbourne's rail network 27/07/2015 at 04:17 #74501 | |
|
Jersey_Mike
250 posts |
" said:The trick is to do it when your signaling, traction power system and rolling stock come up for renewal so you aren't actually incurring additional expense. In the case of Melbourne this would need to be a 20 or so year project, but they did say that a lot of the signaling needs to be renewed so they can start by making any new CTC AC traction compatible. Then you start to purchase dual mode MU's and as line segments need to to have the power systems renewed you install the 25Kv. The other option is to bump up to 3kv DC which might be able to move on a faster timetable. " said: I would so like to agree with you on this point, but then we would both be wrong. The picture in the article clearly shows only 2 OHW structures between the points and the TP (TP= Transition Point. Where the track commences the transition for straight track to curved track). These structures are placed no more than 35m apart. Allowing for a little bit of wriggle room for space between the points and the 1st structure and from the 2nd structure to the TP there would be no more than 90m not the 150m(500ft) that you suggested. By the time you stretch the xover out to remove the diamond xings, you will need a lot more space than the 90m you have.If you look at the overhead (ignore the bridge, I believe the photo pre-dates it) you can see three complete catenary gantries (plus some change before the first one) before the curve takes off. Any slight curvature before the last structure could be re-aligned. " said: Switches at least provide a function. Diamonds are just cost with no utility. " said: Most non-high speed lines in Japan are 1500v DC catenary. Trains serving the greater Tokyo area run every 2mins 30sec peak, 4mins off-peak 21hrs a day, 10 to 15 car trainsets. Most other lines around Japans more densely populated areas, same.I actually hung out with my power systems engineering friend this weekend and mentioned this discussion and his reply was "1,500v DC is the worst electrification system hands down". Basically its all the expensive of overhead lines, but few of the advantages. He mentioned that the Dutch have plans to take their whole country to 25k due to the rampant power issues associated with their current 1.5k system. Log in to reply |
| Six problems ruining Melbourne's rail network 27/07/2015 at 07:59 #74502 | |
|
Mattyq
259 posts |
" said:I actually hung out with my power systems engineering friend this weekend and mentioned this discussion and his reply was "1,500v DC is the worst electrification system hands down". Basically its all the expensive of overhead lines, but few of the advantages. He mentioned that the Dutch have plans to take their whole country to 25k due to the rampant power issues associated with their current 1.5k system. You mean to say that one mans personal opinion........ Bugger it. I can't continue without breaching the forum CoC so I'll stop right here. Not fat ..... fluffy!! (G Iglesias) Log in to reply |
| Six problems ruining Melbourne's rail network 27/07/2015 at 08:33 #74503 | |
|
Danny252
1461 posts |
It's useless to argue with Jersey_Mike - he is always right, and every way that isn't the American way is wrong.
Log in to reply The following users said thank you: kbarber, Mattyq |
| Six problems ruining Melbourne's rail network 27/07/2015 at 09:08 #74504 | |
Steamer
3920 posts |
" said:It's useless to argue with Jersey_Mike - he is always right, and every way that isn't the American way is wrong.He does have a point: high voltage AC is much better than low voltage DC for transmission on overhead lines, from a power loss point of view. Whether it's cost-effective to convert Melbourne's system to 25kV AC is another question, of course. "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Log in to reply |
| Six problems ruining Melbourne's rail network 27/07/2015 at 09:21 #74505 | |
|
kbarber
1711 posts |
" said:
For 'the worst... hands down' it seems to have achieved quite decent coverage. The Dutch plans are very on-off as (lack of) finance dictates. One of those things that would be nice to have, I suspect, without quite enough advantages that it justifies the money it would cost. I believe the Betuweroute has 25kV; I suspect it drops to 1500V where it crosses existing lines and requires dual voltage locos for that reason (can anyone confirm)? It is, of course, a completely new-build route for freight from Rotterdam to Germany, so no conversion involved. Remember there's more than just substations to alter. You need to start with tunnels & overline bridges - perhaps more common in Europe than the US (but certainly a huge issue in suburban and urban areas anywhere you go). Achieving clearances for 25kV is a slightly non-trivial task. Then you may have to alter huge numbers of OHLE structures, which in some cases may have insufficient clearance for the higher voltage. Not to mention any platform canopies etc that run close to the loading gauge anywhere near cantrail level. The new insulators need to maintain existing wire heights & alignments yet provide insulation for the higher voltage, which certainly precludes one-for-one replacement. Where there are vertically-hung insulators that can be a real issue. And you can't get away with standard 25kV insulators either, because they have to support the much greater weight of 1500V catenary. If there are level crossings, you probably have to alter wire height to give sufficient clearances from road vehicles. The list goes on... Then of course there's signalling. Not just immunisation - a huge project in itself, but also ensuring there's protection from the higher voltage for S&T staff, which may well mean a significant number of signal renewals and certainly provision of cages everywhere you don't renew. Renewals will inevitably mean some signals moving, hence possibly further renewals just to accommodate braking distances, quite apart from the sighting issues (which are somewhat non-trivial in any OHLE area and far more difficult with the heavy structures and catenary needed for 1500V). We do have experience of conversion in the UK. In 1949 Liverpool Street - Shenfield was electrified at 1500V DC - at that time regarded as the best system to use. The line from Bow Junction via Gas Factory Junction to Fenchurch Street was also wired, although the Stratford - Fenchurch service was short-lived. Come 1960 or thereabouts, electrification was extended to Southend & Colchester/Clacton and the North East London system (Chingford, Enfield, Hertford East & Bishops Stortford) was also electrified, as was the remainder of the LTS system. By this time 25kV was the accepted norm. But restricted clearances in the inner suburban areas (and through Southend Central on the LTS) made clearances for 25kV impracticable, so a dual voltage system was adopted - 25kV for the outer areas and 6.25kV AC on the difficult stretches. Traction units had an automatic voltage changeover system. I have a feeling (but someone more knowledgable would have to confirm) that the whole of the 1500V area was converted to 6.25kV, with 25kV starting only beyond Shenfield on the main line and Southend line. On the LTS the London end changeover point was at Upney. I'm not sure where the changeover was on the NE London but it could have been as far out as Cheshunt. Although somewhat larger than the 1500V originals, 6.25kV insulators could largely be accommodated without significant alteration - I think the answer was to increase their diameter so that separation between catenary and structures could be left unchanged. By the 1980s, experience with 25kV together the complication of Automatic Power Control fitted to traction units (not to mention its reliability) led to a further conversion, with the whole system being converted to 25kV. This was a much more complex affair and required specially designed insulator assemblies, some giving minimal clearances from OHLE structures. There were also some locations where additional insulation had to be provided on the OHLE structures; I think that was to overcome the pigeon problem! It was a huge job but necessary to allow massive simplification fo the next generation of EMUs (starting with the class 315) and, in due course, the use of electric locos once electrification was extended to Norwich and Kings Lynn. But the complex construction was itself a continuing issue and, as a result, the whole of the former 1500V section from Liverpool St to Shenfield is now being entirely renewed with specially designed catenary supplied by Furrer & Frey. Many of the existing structures continue in use but quite a few completely new structures are required. It's another huge job, been going on since before the Olympics and I would estimate is still little more than half done. But clearances remain substandard/suboptimal and there are certainly locations where the pigeon shields remain necessary. Where practicable, the French solution seems far better - keep the existing 1500V system but (apart from trivial extensions) do all new work at 25kV and use dual-voltage traction. Log in to reply |
| Six problems ruining Melbourne's rail network 27/07/2015 at 11:02 #74510 | |
|
Mattyq
259 posts |
" said:I believe the Betuweroute has 25kV; I suspect it drops to 1500V where it crosses existing lines and requires dual voltage locos for that reason (can anyone confirm)? It is, of course, a completely new-build route for freight from Rotterdam to Germany, so no conversion involved.If the crossing is a diamond crossing, it is not necessary to have dual-voltage locos. In Melbourne, there are three level crossings where 600v DC trams cross the 1500v DC railway. Two of them (Riversdale and Gardiner) are still controlled by lever boxes, the third (Glenhuntly) by OCS panel. If you click on the box names of either level box, a pull chart is shown, detailing the operation of the crossing and how power is managed. Not fat ..... fluffy!! (G Iglesias) Log in to reply |
| Six problems ruining Melbourne's rail network 27/07/2015 at 12:38 #74515 | |
|
Muzer
718 posts |
" said:Where practicable, the French solution seems far better - keep the existing 1500V system but (apart from trivial extensions) do all new work at 25kV and use dual-voltage traction.When you remember that this is now essentially our policy for third rail (keep it, build trivial extensions/fill-in electrification with it, but all new electrified lines should be 25kV overheads), that does lend further credence to the idea that this is probably the most cost-effective option. Worting Jn to Exeter St. David's is likely to be 25kV if it's ever electrified, as is some route from Basingstoke down to Southampton for the ever nebulous electric spine freight project, if it ever happens (this would perhaps be the exception as it was once proposed to convert Basingstoke to Southampton from third rail to overheads, but this seems to have been put on the back burner as they've realised that the big problem is converting the trains...). North Downs Line would perhaps be third rail, perhaps overheads; Hastings to Ashford has been proposed only with overheads I believe, thanks to the convenience of HS1 being at Ashford. Uckfield branch I suspect would be electrified third rail, but I might be wrong there. The proposed short extension of the Merseyrail system to Skelmersdale will be third rail electrified, and the Croxley Rail Link which is a short extension of the Metropolitan Line will be fourth rail electrified, like the rest of the London Underground, with the part of the Watford DC Line that it joins converted to fourth rail (all this means in practice is adding an extra rail electrically connected to the same common ground as the track, for areas where third rail trains have to run, if I recall correctly). Have I missed any major diesel islands in third rail land? My only other thought is that if the electric spine does in the end reach Southampton, it might be benifcial for them to extend the extension (as it were) to at least Bournemouth so that South Coast to North West CrossCountry services can be electric. Log in to reply |
| Six problems ruining Melbourne's rail network 27/07/2015 at 13:50 #74519 | |
|
Steamer
3920 posts |
" said:Have I missed any major diesel islands in third rail land?Not an island as such, but talk of extending the Merseyside 3rd rail system beyond Kirkby to Wigan comes round every few years. The proposed branch to Skemersdale from the same route would likely be third rail as well. "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Log in to reply |
| Six problems ruining Melbourne's rail network 27/07/2015 at 13:53 #74520 | |
|
smw
6 posts |
" said:" said:There are no real crossings on the Betuweroute but it connects to some of the other lines (for diversions) where the trains need to switch from 25kv tot 1500v. The locos are multi-voltage locos (Belgium has 3000v and Germany 15kv) by the way. The tender for new fast services contains also a dual-voltage demand.I believe the Betuweroute has 25kV; I suspect it drops to 1500V where it crosses existing lines and requires dual voltage locos for that reason (can anyone confirm)? It is, of course, a completely new-build route for freight from Rotterdam to Germany, so no conversion involved.If the crossing is a diamond crossing, it is not necessary to have dual-voltage locos. In Melbourne, there are three level crossings where 600v DC trams cross the 1500v DC railway. Two of them (Riversdale and Gardiner) are still controlled by lever boxes, the third (Glenhuntly) by OCS panel. If you click on the box names of either level box, a pull chart is shown, detailing the operation of the crossing and how power is managed. Log in to reply The following users said thank you: Mattyq, kbarber |
| Six problems ruining Melbourne's rail network 27/07/2015 at 15:33 #74523 | |
|
postal
5190 posts |
" said:It's useless to argue with Jersey_Mike - he is always right, and every way that isn't the American way is wrong.Makes a long-haul flight sitting between Maxand and Jersey_Mike an interesting proposition :lol: “In life, there is always someone out there, who won’t like you, for whatever reason, don’t let the insecurities in their lives affect yours.” – Rashida Rowe Last edited: 27/07/2015 at 15:34 by postal Log in to reply |
| Six problems ruining Melbourne's rail network 28/07/2015 at 07:22 #74543 | |
|
maxand
1637 posts |
Luckily for people like you and Jersey Mike I'm totally ignorant of the merits of different voltages.
Log in to reply The following users said thank you: postal, JamesN |