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Miscellaneous TTC Discussion & Questions

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4 hours ago, nfitz said:

I have a standard 220 volt (or is it 240) panel in my house, but I have a 100 Amp entry. When they installed AC here, they said it was a good job it was a newer entry, because the old 40 Amp ones from 100 years ago can't handle the additional load from the AC, even though they were 220 V.

Surely it's the amperage, not the voltage that's the issue. V=IR.

(but the point is moot - A/C works fine ... even when it's 35 degrees and humid out, with poles).

If anything, the contact patch on a pantograph is smaller than a trolley shoe. The greater surface area of the trolley shoe would handle amp spikes with less resistance.

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The current draw limit would be based on either the electronics for the pole supports less current (a bottleneck somewhere) or the transformer supplying the overheads can't handle all the cars with their AC on (which is nor a pole problem).

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3 hours ago, Xtrazsteve said:

... or the transformer supplying the overheads can't handle all the cars with their AC on (which is nor a pole problem).

That doesn't seem likely, as I rode 501/504 during the heatwaves late last summer with full A/C - and that was a LOT of Flexities on Queen East!

So what's the source of this urban myth that the cars get more power with pantograph than the trolley pole?

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51 minutes ago, nfitz said:

That doesn't seem likely, as I rode 501/504 during the heatwaves late last summer with full A/C - and that was a LOT of Flexities on Queen East!

So what's the source of this urban myth that the cars get more power with pantograph than the trolley pole?

I believe something like this was written in an old CEO report at one time but those are always half BS at times.

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19 hours ago, Cityflyer said:

On the regular wiki for the TTC Streetcars page, it says trolley pole reduces performance for Flexity cars due to 50% less performance / having no A/C during summer. I haven't been on Flexities on a non panto route during summer to test if the A/C works.

This is a regularly occurring rumour/story. And it's bullshit.

 

The cars run just fine on trolley poles with no performance degradation.

 

13 hours ago, Xtrazsteve said:

The current draw limit would be based on either the electronics for the pole supports less current (a bottleneck somewhere) or the transformer supplying the overheads can't handle all the cars with their AC on (which is nor a pole problem).

That was a problem many years ago, but it was resolved several years back - they have upgraded a couple of the substations, added 2 more, and upgraded the feeds.

 

9 hours ago, nfitz said:

So what's the source of this urban myth that the cars get more power with pantograph than the trolley pole?

There was an internal TTC report from about 15 years ago where they tested an ALRV that had been modified to pull the same number of amps as was expected from a Flexity. And during the testing, the draw was high enough to turn the shoe red. I've not been able to get this report, but the engineer leading the project (who I believe is no longer with the TTC) also made a presentation to one of the various engineering societies where he showed the TTC's findings, including relating the report of the red-hot shoe.

 

The problem is that they used a CLRV shoe (3.5" long) versus an ALRV shoe (6" long) for the testing, so of course there will be resistance heating and draw issues. The Flexities are using a modified version of the ALRV shoes and have shown no adverse affects.

 

Dan

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On June 10, 2020 at 9:12 AM, smallspy said:

This is a regularly occurring rumour/story. And it's bullshit.

 

The cars run just fine on trolley poles with no performance degradation.

 

That was a problem many years ago, but it was resolved several years back - they have upgraded a couple of the substations, added 2 more, and upgraded the feeds.

 

Yeah, I remember thinking back when the handwringing about this started up that if power consumption on the new cars was projected to be so bad, it was going to affect a lot more power distribution infrastructure beyond the end of the trolley pole and commented on a number of Steve Munro’s articles to that effect and asked a few times if there were any plans to deal with that.  Unfortunately, with the local understanding of electrical engineering extending to an “OMG the HCRR substation’s gonna explode if the diode protection diodes aren’t installed before the CLRVs arrive” level of yeah, there weren’t any very good answers forthcoming back then.  I’m glad the TTC has someone in house that understands the peak current draw, safety margin, and how that goes back through rating all of the infrastructure from current collector and trolley wire all the way back to utility primary feeds at substations.

 

Quote

There was an internal TTC report from about 15 years ago where they tested an ALRV that had been modified to pull the same number of amps as was expected from a Flexity. And during the testing, the draw was high enough to turn the shoe red. I've not been able to get this report, but the engineer leading the project (who I believe is no longer with the TTC) also made a presentation to one of the various engineering societies where he showed the TTC's findings, including relating the report of the red-hot shoe.

I think there’s a copy of the report/presentation on the APTA website; I read through a copy a couple of years ago. It’s out there if anybody interested wants to take a look.

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On 6/9/2020 at 1:47 PM, Cityflyer said:

On the regular wiki for the TTC Streetcars page, it says trolley pole reduces performance for Flexity cars due to 50% less performance / having no A/C during summer. I haven't been on Flexities on a non panto route during summer to test if the A/C works.

Is it true that all streetcars routes during summer besides 509/510/512 are running with no A/C?

They couldn't keep them in service for too long with the A/C not running. They do have some passenger windows for a situation where the A/C fails, but they are locked. Just like on the buses with the windows locked, the driver isn't able to unlock the windows without a key. Those streetcars would get pretty inhumane fairly quickly with no ventilation.

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3 hours ago, Turtle said:

They couldn't keep them in service for too long with the A/C not running. They do have some passenger windows for a situation where the A/C fails, but they are locked. Just like on the buses with the windows locked, the driver isn't able to unlock the windows without a key. Those streetcars would get pretty inhumane fairly quickly with no ventilation.

Exactly.  The TTC learned this the hard way on the CLRVs in 1980.

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19 hours ago, Wayside Observer said:

 

Yeah, I remember thinking back when the handwringing about this started up that if power consumption on the new cars was projected to be so bad, it was going to affect a lot more power distribution infrastructure beyond the end of the trolley pole and commented on a number of Steve Munro’s articles to that effect and asked a few times if there were any plans to deal with that.  Unfortunately, with the local understanding of electrical engineering extending to an “OMG the HCRR substation’s gonna explode if the diode protection diodes aren’t installed before the CLRVs arrive” level of yeah, there weren’t any very good answers forthcoming back then.  I’m glad the TTC has someone in house that understands the peak current draw, safety margin, and how that goes back through rating all of the infrastructure from current collector and trolley wire all the way back to utility primary feeds at substations.

Thankfully, I think it's even better than that.

 

A lot of the work that was done was at the outer ends of the system where problems such as undervoltage and stray grounds were constant and recurring problems. While they weren't really a major issue with the PCCs or even the CLRVs to any great degree, undervoltage situations were perceived to be a major potential issue with the computer systems of the Flexities - thus, they fixed them. (My understanding is that while undervoltages can be bad for computers that they can be resolved through careful planning in a system as complex as a streetcar, although I will certainly defer to the experts on this.)

 

19 hours ago, Wayside Observer said:

I think there’s a copy of the report/presentation on the APTA website; I read through a copy a couple of years ago. It’s out there if anybody interested wants to take a look.

I'm pretty sure that I saved a copy of it on my computer. If I can dig it up, I'll gladly attach it to a post.

 

Dan

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1 hour ago, smallspy said:

A lot of the work that was done was at the outer ends of the system where problems such as undervoltage and stray grounds were constant and recurring problems. While they weren't really a major issue with the PCCs or even the CLRVs to any great degree, undervoltage situations were perceived to be a major potential issue with the computer systems of the Flexities - thus, they fixed them. (My understanding is that while undervoltages can be bad for computers that they can be resolved through careful planning in a system as complex as a streetcar, although I will certainly defer to the experts on this.)

Stray grounds are an interesting beast.  The fear of that on part of the telephone company in Cincinnati is the reason why streetcars got the double poles there with the trolleybus style dedicated return circuit in the overhead.  Stray ground currents don't actually affect the streetcars themselves but the problem as it pertains to the cars themselves is that as streetcar power consumption goes up, so does the current passing through the return paths including the stray paths and that's not a good thing.  Stray ground currents eat underground utilities, literally eat pipes and wires up with electrolytic corrosion.  Also, when you get huge traction currents or significant portions of them being carried by the water or natural gas mains etc, it poses a serious shock hazard to utility crews.  I remember talking with someone from SEPTA a few years ago and they had to stop streetcar service on Island Ave. for an afternoon because a Philadelphia Gas Works crew that was working on a main was observing sparking whenever trolleys went by.  You for sure want to get the ground return side of things in order before jacking up the total current the power infrastructure's being asked to handle on the account of larger cars.

Funny enough you mention computers and undervoltage since I was at a BBQ on Saturday with a bunch of other electronics guys.  One guy who's got a career job and teaches college courses on the side and I were talking about embedded systems and writing interrupt service routines.  He was mentioning a job interview gone wrong where the candidate totally choked on questions about the brownout interrupt on some microcontroller he professed expertise on in his resume.  It's a hardware interrupt that gets activated when the power management part of the chip detects and undervoltage condition so you can catch the interrupt in software and jump to a section of code where you orderly clean up after the power fluctuation.  Useful for doing a graceful shutdown or cleanup or move into a safe operating condition for whatever thing it is you're putting the embedded micro into.  Alternatively, it's also a good argument for keeping your control system on an isolated set of power rails from the rest of your thingey so if too many motor loads etc. get fired at the same time, they won't drag down the power feed to the controls.

Anyways, on a streetcar, you've got a generous difference between the incoming 500-750 V and the various +/- 12 V (old school!), 5 V, 3.3 V and other lower voltage rail voltages so what you're confronted with here is a classic line/load regulation power conversion situation.  Going from 500 volt-ish undervoltage line conditions through to whatever the low voltage supply is on the streetcar isn't a huge problem with switching converters since they've got huge regulation ranges on the input and output sides compared to old school stuff like motor generator sets.  Then you have another DC to DC converter providing the even lower DC rails used in the computer system fed off the low voltage supply on the streetcar which itself is also propped up by the batteries so if you get to the point of browning out the streetcar's onboard computer system, you've either got severe LVPS issues on board the car or really gross/completely absent overhead line power, by the time you get regulator dropout happening and the low voltage rails are collapsing, you've got bigger problems to worry about than the state the computer's in.

The whole how well or not newer streetcars handle lower line voltages has been the subject of debate at a number of trolley museums eyeing LRV acquisitions starting about 10 years ago since line voltage drop at maximum distance from the substation can be pretty severe at some places.  I had a long three way text message conference during an extended length coffee break with a couple Friends of Philadelphia Trolleys people about a week ago because some misconceptions on getting current measurements to set up limit relays and ABR coils on PCC cars and line voltage measurements and the instrumentation used for doing it were causing confusion.  I ended up rigging up a demo setup on my workbench at home with a ton of stuff to do it different ways in scale with a model train engine and take measurements on that using 6 volts at 1 amp instead of 600 at close to 400 A and shot a pair of short videos and sent them off.  Got a nice thankyou note since they helped a lot.  The guys at that BBQ on Saturday thought the instructional videos were great too as did a couple of other people at work I showed them to.  If borders were open, it'd have been a real live demo on a real live PCC car, but oh well.  You work with what you've got available under the circumstances.

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On the off chance anybody’s interested, here are a couple of pictures of the FPT PCC car measurements demo I did on the bench since access to the real thing for a 1:1 scale real live example is severely restricted right now.  The same principles apply to TTC PCCs so nobody get into a snit about the off topic.

9C5C4EEC-97A1-4D94-AE7E-E951FC688A1D.thumb.jpeg.ffd773e3c05517fade7e6daff16cb633.jpeg

F5990A76-BCBF-49DE-A1C7-626DA6715EB1.thumb.jpeg.de74e4f664e18b073caa12f844adc7f6.jpeg

The rig.

053FF2EA-4496-4D42-9D0E-F3121F30B31E.thumb.jpeg.290aa5c906363ef990f4d2e1edcb847e.jpeg

One if these is not like the other.

C37DD898-5EC9-4D22-A540-A7A4C90F331C.thumb.jpeg.5ec73d1d3c07686b6e429dfa773ea180.jpeg

When resistance values get small, the four wire Kelvin setup is the way to go.  Two wire measurements give bogus results. Those of you who have been reading your vintage GE and WH publications know why that’s an issue with transit equipment.

A real PCC car would’ve been more fun.

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Question for the mechanically inclined people here, the Nova LFS with the rear door push bar I’ve noticed has different response times on different agencies. OC Transpo for example when the rear door interlock is engaged the back doors have a 2-4 second delay to actually engage ( green light on ) whereas the TTCs seem to have no delay at all, bus stops, interlock switch on and green light simultaneously and open door. Is there a program attached with this delay? The curiosity had been getting to me 

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44 minutes ago, ZümmyZüm said:

Question for the mechanically inclined people here, the Nova LFS with the rear door push bar I’ve noticed has different response times on different agencies. OC Transpo for example when the rear door interlock is engaged the back doors have a 2-4 second delay to actually engage ( green light on ) whereas the TTCs seem to have no delay at all, bus stops, interlock switch on and green light simultaneously and open door. Is there a program attached with this delay? The curiosity had been getting to me 

Try an artic or the 8xxx novas, you'll see a huge difference compared the the 3xxx newer ones. The older is a mechanical control while the newer is electronically controlled. 

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9 minutes ago, Xtrazsteve said:

Try an artic or the 8xxx novas, you'll see a huge difference compared the the 3xxx newer ones. The older is a mechanical control while the newer is electronically controlled. 

True, I should be more specific, diesel 40ft with air doors and not electric, are the newest 3xxx much faster with the rear door compared to their older counterparts? 

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3 hours ago, ZümmyZüm said:

True, I should be more specific, diesel 40ft with air doors and not electric, are the newest 3xxx much faster with the rear door compared to their older counterparts? 

Yes the electric powered rear doors are faster than the air controlled ones.

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5 hours ago, Xtrazsteve said:

Try an artic or the 8xxx novas, you'll see a huge difference compared the the 3xxx newer ones. The older is a mechanical control while the newer is electronically controlled. 

The air engines are triggered by electric solenoid valves, at the doors themselves,  so the control circuit is almost identical.

air lines haven’t been routed through the handle since the Orion V.

6 hours ago, ZümmyZüm said:

Question for the mechanically inclined people here, the Nova LFS with the rear door push bar I’ve noticed has different response times on different agencies. OC Transpo for example when the rear door interlock is engaged the back doors have a 2-4 second delay to actually engage ( green light on ) whereas the TTCs seem to have no delay at all, bus stops, interlock switch on and green light simultaneously and open door. Is there a program attached with this delay? The curiosity had been getting to me 

All those parameters are theoretically customizable in the multiplex software.

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Is it normal that TTC ships the Toronto Streetcars to Bombardier? The reason I asked this is because this weekend I saw 2 streetcars being shipped by freight in south shore Montreal, the first was 4418 and the latest was 4410 and I was shocked that I saw 2 different streetcars in 3 days 

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1 hour ago, Transitfan39 said:

Is it normal that TTC ships the Toronto Streetcars to Bombardier? The reason I asked this is because this weekend I saw 2 streetcars being shipped by freight in south shore Montreal, the first was 4418 and the latest was 4410 and I was shocked that I saw 2 different streetcars in 3 days 

About 60 or so of the earlier ones are going to La Pocatiere from Toronto for warranty repairs on the shoddy Bombardier Mexico welding. With the state of emergency, they recently decided to send more at once, because less are in service - so there's been more than usual heading out in recent days. Used to be only 6 or 7 at once, but I think it's supposed to be near double that for a few months.

There's a running commentary in the end of:

 

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This motivated me to look up exactly where La Pocatière is. It's on the south shore of the St Lawrence (river or gulf), maybe 50 or 60 km east (north-east) of Québec. It's a nice sunny 22º there right now.

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