Metra Electrification

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REM wants to have the Mount Royal Tunnel all for themselves, meaning no trains from VIA and Exo allowed.

Also the only DC voltage France uses is 1500 V DC.
Either way, the fact that Mount Royal Tunnel is being hijacked by REM has very little to do with whether it is electrified using 1500DC or 25kV AC. If they wanted it to be shared the type of electrification is not something that would prevent such sharing. That was my point. You were trying to use that as an argument about METRA needing to change their electrification of existing line. That really is a very weak argument since it is not really the issue in Mount Royal Tunnel. The issue there is mostly other considerations.

It appears that it is a rail advocacy group that is the only one upset about the plan. Even VIA does not appear toc are much, much to the bewilderment of the author of the article. I have no idea how widespread the authors view is shared by anyone on this matter anyway. If REM provides for a much greater utility of the tunnel, then maybe it does make sense for VIA to use a different routing to get to Quebec. But all that is out of scope of this thread.
 
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Either way, the fact that Mount Royal Tunnel is being hijacked by REM has very little to do with whether it is electrified using 1500DC or 25kV AC. If they wanted it to be shared the type of electrification is not something that would prevent such sharing. That was my point. You were trying to use that as an argument about METRA needing to change their electrification of existing line. That really is a very weak argument since it is not really the issue in Mount Royal Tunnel. The issue there is mostly other considerations.

It appears that it is a rail advocacy group that is the only one upset about the plan. Even VIA does not appear toc are much, much to the bewilderment of the author of the article. I have no idea how widespread the authors view is shared by anyone on this matter anyway. If REM provides for a much greater utility of the tunnel, then maybe it does make sense for VIA to use a different routing to get to Quebec. By all that is out of scope of this thread.

Seems I should bring this to the DMs then
 
Indian Railways runs 24' tall double stack on flat cars under 26' high catenary.

NJT runs 14'6" tall MLVs under 16' 6" clearance over bridges with 25kV catenary.

Why on earth would you require catenary at 25'? Just because California chose to do so?

Safety clearance for 25kV is something like 1.5' so clearance from train roof to contact wire and 1.5' clearance from contact wire to ceiling, i.e. a total of roughly 3' above train roof is sufficient, a little less if ceiling rails embedded in insulating material are used in covered areas instead of full blown catenary like every sane rail agency in the world does. KISS's are 16' - 16.5' tall (depending on which country's version one is talking about). So ceiling clearance of 19.5" should be fine with contact wire at 18' or so. So dig ~2.5' or so, not 8'.

I think according to physicists, air can insulate up to 3kV per millimetre which means a foor of air can tolerate 300 x 3kV = 900 kV. That means it can hold 25kV 36 times over.

According to engineers, the figure is closer to 1 kV per millimeter, but that's still 300 kV that a foot of air can tolerate. that means it can hold 25kV 12 times over.

Of course in reality you wouldn't want to take it anywhere near the limit as the slightest misalignment or something like a bird flying between train and wire could cause an arc to strike. You need to take into account that the 25kV cable must not just be at a safe distance from the train but also from the ceiling and other structures, and that the catenary needs space to move in dynamically, and that the the train bounces on its springs and other such effects. In locations with clearance problems such as legacy tunnels they also sometimes use rigid overhead conductors rather than catenary cables to save space.
 
I was wondering if it would be possible to fit 25 kV 60 Hz AC electrical equipment within the space used for the 1500 V DC electrical equipment given its design. If so then they wouldn't have to buy the Stadler EMUs that Caltrain will be using. I was bringin up Stadler providing bilevel electric EMUs for Metra and NICTD because the Highliner II's are literally the Gallery Cars (which both Caltrain and Metra use) but as EMUs and Caltrain's gonna replace the gallery cars with those. Plus they're roomier than the Gallery Cars.

Maybe it would be possible, but it might take some customization and hence less use of off the shelf components and hence higher costs. I cannot right now think of any examples of such a conversion having been done from DC to AC. But that doesn't mean to say that somebody hasn't done it somewhere somehow. Advancement in power electronics means the cabinets required are now much smaller than they used to be.
 
In going to HV AC the usual problem is finding space for the heavy transformer at a location that does not adversely affect the ride and stability of the car. Usually such space is easy to find in high floor cars. Harder in low floor cars.

In engineering electrification systems, for 25kV catenary usually 10" - 12" clearance is used, more so if you are near the sea and in humid atmosphere.

Inside tunnel the clearance above the contact surface can be reduced considerably if the contact rail is mounted on continuous insulating surface and the tunnel roof is covered with insulating material all the way to prevent sparkover from the pantograph.
 
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NJ Transit converted the E-L line from DC to 25Kv AC.-
One of the world's biggest 1500v DC to 25kV 50Hz AC conversion was that of the suburban network around Mumbai. Before that there was a much smaller conversion of 3kV DC to 25kV 50Hz AC in part of the suburban network of Kolkata where the rest of the massive network was then electrified using AC through the '60s and early '70s. Now the railways in state of West Bengal, where Kolkata is located is about to become fully electrified next year.

One difference between Mumbai and Kolkata was that in Kolkata the DC electrification was short lived and it was converted as soon as AC electrification came to its boundary. In Mumbai they electrified everything outside the suburban network using 25kV AC before they tackled the conversion. It involved increasing clearance through many tunnels on the Bhore Ghat and Thal Ghat ramps up from the coastal plains to the Deccan Plateau escarpment. For a long period they used dual voltage equipment to run through trains. But most LD trains changed engines at the traditional end point of DC electrification loco change points - Igatpuri (towards Kolkata) and Pune (towards Chennai). Delhi train to North ran through with dual voltage engines part of the way before changing engine to AC.

In the case of METRA, if clearance is a problem for HV which is not easily or cost effectively fixed, they could use lower voltage electrification at constricted places without giving up the advantages of 25kV in the trunks which presumably do not have vertical clearance problems that aren't easy to fix.

One reason that NY Penn Station may never be upped from 12kV is clearance issues, even if the trunks outside of the clearance issue area is converted to 25kV some day, though converting from the 12kV 25Hz single phase synchronous network to 25kV 60Hz 3 phase commercial feed network is a huge undertaking. MNRR in Connecticut managed to convert from ~12kV 25Hz single phase system to 12.5kV 60Hz 3 phase commercial feed, but it took them years to get there. The conversion of the entire system to constant tension catenary is taking even longer, and sin;t quite done yet.
 
One reason that NY Penn Station may never be upped from 12kV is clearance issues, even if the trunks outside of the clearance issue area is converted to 25kV some day, though converting from the 12kV 25Hz single phase synchronous network to 25kV 60Hz 3 phase commercial feed network is a huge undertaking.

What's the vertical clearance of the North and East River Tunnels when compared to the Mount Royal Tunnel (a tunnel with very similar height restrictions)? If they're similar enough to Mount Royal Tunnel then converting NY Penn Station to 25 kV 60 Hz could be doable (it would also enable Metro-North to operate their M8s into Penn Station as they cannot run on 12 kV 25 Hz AC (but can run on 25 kV 60 Hz AC).

MNRR in Connecticut managed to convert from ~12kV 25Hz single phase system to 12.5kV 60Hz 3 phase commercial feed, but it took them years to get there. The conversion of the entire system to constant tension catenary is taking even longer, and sin;t quite done yet.

Seems it'd be possible for them to convert it to 25 kV 60 Hz AC in the future. That's how NJT converted the Matawan-Long Branch segment from 12 kV 60 Hz to 25 kV 60 Hz.
 
What's the vertical clearance of the North and East River Tunnels when compared to the Mount Royal Tunnel (a tunnel with very similar height restrictions)? If they're similar enough to Mount Royal Tunnel then converting NY Penn Station to 25 kV 60 Hz could be doable (it would also enable Metro-North to operate their M8s into Penn Station as they cannot run on 12 kV 25 Hz AC (but can run on 25 kV 60 Hz AC).
Someone who once upon a time worked as chief engineer of projects around Penn Station told me that that there would be significant cost to create additional clearances in Penn station, so while given additional money it is doable, there are much more urgent uses for any additional money to do more pressing things. conversion of electrification system is a very very low priority since nothing is broken. So it is unlikely to happen anytime soon. This gentleman then went on to work on NEC track upgrade projects, then onto ARC and Gateway, and finally left Amtrak to move on to Parsons, still remaining involved with Gateway.

Anyway, the bottom line is that there is enormous costs involved to replace the 25Hz system by a 60Hz system with very little gain. So Amtrak has been enhancing the 25Hz system with additional static converter feeds from commercial sources. It is not going away anytime soon.

It is much easier and cheaper for Metro North to acquire 25Hz capable EMUs than to convert electrification in Penn Station. Actually what they plan to do is extend LIRR third rail upto CP Gate where the 60Hz electrification ends and 25Hz electrification begins, and run M8s into Penn Station using 3rd rail DC, which of course is the least cost alternative at present. They would need to do so anyway to use the West Side Yard, since LIRR will never string wires over it.
Seems it'd be possible for them to convert it to 25 kV 60 Hz AC in the future. That's how NJT converted the Matawan - Long Branch segment from 12 kV 60 Hz to 25 kV 60 Hz.
Matawan - Long Branch bears no similarity to Penn Station. Matawan - Long Branch was electrified for 25kV 60Hz. Initially it was energized at 12.5kV 60Hz by center tapping the secondary side of the transformer to allow Arrows to operate through since they cannot change voltage on the fly. Once they got enough ALP44s, ALP46s and trailer coaches to discontinue use of Arrows beyond Matawan they reverted to use the full secondary coil on the transformers to get to 25kV as originally designed, since the ALPs can change voltage on the fly.

Why on earth would MNRR want to convert to 25kV? Except for a small subfleet, specially being built for operation east of New Haven on service to New London, their M8s are incapable of operating on 25kV.
 
Matawan - Long Branch bears no similarity to Penn Station.

I was comparing Matawan-Long Branch to Metro-North's New Haven Line.

Why on earth would MNRR want to convert to 25kV? Except for a small subfleet, specially being built for operation east of New Haven on service to New London, their M8s are incapable of operating on 25kV.

Aren't the M8s multi-system and can change between 12 kV 60 Hz and 25 kV 60 Hz on the fly? That's what I heard
 
I was comparing Matawan-Long Branch to Metro-North's New Haven Line.
The MNRR electrification is not designed for 25kV, so it will most likely need additional, possibly quite expensive, civil clearance work for the higher voltage. The Long Branch electrification was designed for 25kV when it was built.
Aren't the M8s multi-system and can change between 12 kV 60 Hz and 25 kV 60 Hz on the fly? That's what I heard
Only the east of New Haven subfleet, not the majority of the fleet. A money saving exercise by MNRR, as they wanted as many cars as they could get. So they took the absolute lowest cost package.
 
Well, that's silly. However, I'm sure that the non-multisystem-M8s can be retrofitted; if they're on the same base structure as the multisystem M8s, there is physical room to implement the necessary hardware. It's not like trying to add pantographs and AC pickup to the M7 or M9, which is probably impossible.
 
Anyway, the bottom line is that there is enormous costs involved to replace the 25Hz system by a 60Hz system with very little gain. So Amtrak has been enhancing the 25Hz system with additional static converter feeds from commercial sources. It is not going away anytime soon.

It used to add a lot of cost to EMU purchases, because handling multiple frequencies was a HUGE PAIN. Did something change technologically? Perhaps with electronic rectifiers, you can design one which can handle any incoming frequency?

Back when it added huge costs to EMU purchases, there was a huge gain in replacing the 25Hz system with a 60Hz system. What changed?

Multi-voltage has been relatively easy for a long time (after all, voltages droop and spike anyway; you have to be able to handle variable voltage), but multi-frequency was hard. That's part of why Metro-North thought that standardizing the frequency to avoid frequency-switching was worth it, but standardizing the voltage wasn't (since higher voltage requires higher structure clearances, but changing frequency requires absolutely no structure changes).

It is much easier and cheaper for Metro North to acquire 25Hz capable EMUs than to convert electrification in Penn Station.
Is it? Why? What changed technologically?

Actually what they plan to do is extend LIRR third rail upto CP Gate where the 60Hz electrification ends and 25Hz electrification begins, and run M8s into Penn Station using 3rd rail DC, which of course is the least cost alternative at present. They would need to do so anyway to use the West Side Yard, since LIRR will never string wires over it.

I was told that the newest of the M9s are supposed to have shoes which can do DC pickup from both LIRR overrunning third rail and Metro-North underrunning third rail without any manual "get out and have repairmen alter the train" changes. This, if true, would make this straightforward, of course.

But this is new. Even the first batch of M9s, the newest cars in service, can't do that. It would have certainly been a pain in the neck with the older cars. I am curious as to how the new "automatic flip shoes" work.
 
Yes, the big change is in the architecture of the drive system driven by the availability of solid state power electronics technology.

Today whatever is fed to the engine is converted to something around 3kV DC for the link bus. Then the users of the power, namely the motor drives and hotel power are all fed from the link bus through appropriate solid state modules that create the right kind of AC with the right waveform and frequency. Almost no new passenger equipment is built with DC motors any more.

One thing that this architecture does is that it completely isolates the control circuitry from the nature of the high voltage feed. The only components affected are the primary HV transformer and the rectifier to feed the link bus, and also incidentally the feed from regeneration to the HV side, which again is usually through the link bus.

So the issue of line frequency then remains relevant only to the capability of the transformer and rectifier. Rectifiers generally are relatively insensitive to frequencies. Transformers have to have adequate sized cores to carry the power needed. Lower frequencies require larger cores, but a transformer capable of handling the necessary power at lower frequency will work fine with higher frequency.

Before the current architecture became feasible, the control system used tap changers on the secondary side of the transformer and fiddled around with power in AC form before feeding it through a rectifier to DC motors. So they were more exposed to line frequency, but still equipment like Arrow IIIs were built to handle both 25Hz and 60Hz a long time back, even though they had DC motors in their original incarnation.

Now the flip side is that any extra capability costs extra money, so one does not willy nilly add extra capability when you have no plan to use it. But merely adding the ability to handle 25Hz and 60Hz in effect just makes the transformer a little heavier, and costs slightly more. OTOH converting the existing 25Hz electrification to 60Hz is an enormously complex, quite expensive and time consuming process. Some day, when everything around New York becomes electrified at 12.5kV or 25kV 60Hz, it may be time to consider taking the leap, like they did in Mumbai with their 1.5kV DC system. But for now that effort is probably better expended in more pressingly needed projects.
 
Conversion to 60Hz being Complex is definitely the word. The 25 Hz has powered the signal system, many station services, repair facilities/ Many motors for these facilities are 25 Hz which will require replacing. You don't want your escalator running over twice as fast! But signal system conversion is most difficult. Designing the signal system + ACSES to operate both at 25 Hz and swapping to 60 Hz immediately can be very difficult +. Amtrak has been installing commercial 60 Hz back up supplies for each of the signal systems locations but do not know how far along that has proceeded ?

Of course conversion has already started with the Hell Gate conversion that took over a year ? Just about 12 miles. So converting 249 miles would take 20 years? That does not include the various yards.

As to where Amtrak would start maybe WASH then north. But probably last section would be the area around PHL due to problems with coordination with SEPTA ?
 
So back to Metra....

(though this is an interesting discussion)

At the moment I don't see any reason to change the electrification or rolling stock or infrastructure. I could see it once another line was electrified (or plans being made to do so). Then a big bulk older for new rolling stock or converting the new Highliners which are not old by Metra standards. One thing that was discussed, I think for the Rock, was battery powered trains of some kind if I remember right.

That said, I think Metra wants to replace their older (oldest in nation in regular use iirc) cars first, get the system back into good order before tackling a big infrastructure project on an entire line, they want to increase service to LaSalle St first and stuff like that (and I hear through the grapevine that they are hiring again, although not sure for what positions).
 
Conversion to 60Hz being Complex is definitely the word. The 25 Hz has powered the signal system, many station services, repair facilities/ Many motors for these facilities are 25 Hz which will require replacing. You don't want your escalator running over twice as fast! But signal system conversion is most difficult. Designing the signal system + ACSES to operate both at 25 Hz and swapping to 60 Hz immediately can be very difficult +. Amtrak has been installing commercial 60 Hz back up supplies for each of the signal systems locations but do not know how far along that has proceeded ?
There are only small residues of the signaling system that depend on the existence of 25Hz power supply. There is no station hotel power that uses 25Hz anymore, so those are mostly non issues. The only major issue is converting from a single phase synchronized power supply to 3 phase commercial power supply.

If just using 60Hz was the goal, then I guess the quickest way to get there would be replace the 25Hz converters by 60Hz single phase converters. But that seems to be somewhat pointless spending of money and effort. Doing a more complete job involves changing the entire feed transmission lines architecture and deployment, is a big challenge and extremely disruptive.
Of course conversion has already started with the Hell Gate conversion that took over a year ? Just about 12 miles. So converting 249 miles would take 20 years? That does not include the various yards.
It is quite a stretch to claim that since all that was done was to use MNRR substation feed to power the Hell Gate Line upto CP Gate. That helps off load the 25Hz system of that load and helps Penn Station with a little more power.

There is no plan to go any further with that at present. Amtrak just installed a whole bunch of new static converters too bolster the 25Hz system feed at Metuchen and Hamilton. So the trunk line in NJ or the Penn Station complex is not getting converted in the next many decades. And before that they just finished bringing on line a huge static converter station in PA (Richmond? @PRR60 correct me if I am wrong) which promptly made it into the news during the great catenary power failure a few years back due to some weird pilot error by the power director.
 
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There is no plan to go any further with that at present. Amtrak just installed a whole bunch of new static converters too bolster the 25Hz system feed at Metuchen and Hamilton. So the trunk line in NJ or the Penn Station complex is not getting converted in the next many decades. And before that they just finished bringing on line a huge static converter station in PA (Richmond? @PRR60 correct me if I am wrong) which promptly made it into the news during the great catenary power failure a few years back due to some weird pilot error by the power director.

The Metuchen converter capacity was increased from 25 to 80 MW and a new traction substation was added at Hamilton. Hamilton has no converters.

The Richmond converter station (located in Philadelphia near the Delair Bridge) has 180 MW capacity and was indeed the epicenter of the May 25. 2006 Amtrak 25 Hz blackout. The root cause was the failure of a programmable logic controller (PLC) at Richmond. PLC's are the interfaces between the Supervisory Control and Data Acquisition (SCADA) system and the local facility controls that permits remote operation of the converter from the Amtrak power dispatch center.

On May 23, work was performed at Richmond that required imposing a temporary output limit of 90 MVA. That limit was applied by the dispatcher through SCADA on May 23. The work was completed the evening of May 23 and the dispatcher removed the limit, but one of the two PLC's at Richmond failed and, unknown to the dispatcher, the 90 MVA (72 MW) limit remained in place. The power system was configured assuming 180 MW capacity from Richmond. The system survived the supply shortfall through the morning and afternoon peaks on May 24, although some unusual voltage fluctuations and a Sunnyside converter tripping on overload were hints that something was amiss. Given that electric traction systems by nature have varying voltage and loads, the hints were missed on May 24. The May 25 morning peak exceeded actual system supply capacity, voltage fluctuated wildly, one-by-one the converters overloaded and tripped, finally the dispatchers manually tripped the Safe Harbor generators to prevent destruction, and that was that.
 
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Yes, the big change is in the architecture of the drive system driven by the availability of solid state power electronics technology.

Today whatever is fed to the engine is converted to something around 3kV DC for the link bus. Then the users of the power, namely the motor drives and hotel power are all fed from the link bus through appropriate solid state modules that create the right kind of AC with the right waveform and frequency. Almost no new passenger equipment is built with DC motors any more.

One thing that this architecture does is that it completely isolates the control circuitry from the nature of the high voltage feed. The only components affected are the primary HV transformer and the rectifier to feed the link bus, and also incidentally the feed from regeneration to the HV side, which again is usually through the link bus.

So the issue of line frequency then remains relevant only to the capability of the transformer and rectifier. Rectifiers generally are relatively insensitive to frequencies. Transformers have to have adequate sized cores to carry the power needed. Lower frequencies require larger cores, but a transformer capable of handling the necessary power at lower frequency will work fine with higher frequency.

Before the current architecture became feasible, the control system used tap changers on the secondary side of the transformer and fiddled around with power in AC form before feeding it through a rectifier to DC motors. So they were more exposed to line frequency, but still equipment like Arrow IIIs were built to handle both 25Hz and 60Hz a long time back, even though they had DC motors in their original incarnation.

Now the flip side is that any extra capability costs extra money, so one does not willy nilly add extra capability when you have no plan to use it. But merely adding the ability to handle 25Hz and 60Hz in effect just makes the transformer a little heavier, and costs slightly more. OTOH converting the existing 25Hz electrification to 60Hz is an enormously complex, quite expensive and time consuming process. Some day, when everything around New York becomes electrified at 12.5kV or 25kV 60Hz, it may be time to consider taking the leap, like they did in Mumbai with their 1.5kV DC system. But for now that effort is probably better expended in more pressingly needed projects.
Back in the day, it was not as easy to make the rectifiers and transformers handle multiple frequencies. The old rectifiers weren't happy with major frequency changes. I appreciate the explanation of the architecture which makes it trivial; it makes sense. I suppose for regen you need an alternator? Those are electronic and solid state now too, and don't care about frequencies... But weren't in the past. Makes sense. Tech moves on!

I am still curious about the shoes which can handle MN and LIRR third rails without difficulty.
 
It seems amazing that the 25 Kv 50 or 60 Hz standard still has not made thru the western world. In fact some new DC CAT is still being built for intercity rail in eastern Europe. Granted DC is cheaper initially as Impedance bonds are not needed for DC CAT signaling. However the EU is pushing AC by giving higher grants for AC 25 Kv.
 
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