Streetcar News

[Turtle]

19 hours ago, Ed T. said:

By the way, Steve Munro has now also done an examination of travel times on St. Clair over the years.

https://stevemunro.ca/2021/08/13/travel-times-on-512-st-clair/

https://stevemunro.ca/2021/08/11/how-slow-is-the-510-spadina-car/

Even though Steve Munro seems to think differently, I can confirm that double stopping is a problem on St. Clair. Signal priority is not great there.

[Shaun]

Why is that so difficult to fix? We have GPS technology and predictive modeling that could time the lights to be green when the streetcar arrives. 

[Xtrazsteve]

5 hours ago, Shaun said:

Why is that so difficult to fix? We have GPS technology and predictive modeling that could time the lights to be green when the streetcar arrives. 

It's not that simple. Giving Spadina more green means longer cycles and more delays on east-west. It's not a good solution in the long run either.

They should just get rid of the left lanes and force cars to use side streets instead and move the stops nearside. That way they get rid of the double stopping and the left turning phase. They can improve speed further if the TTC upgrade the special works to modern switches and ditch those stop and proceed rules. Then fence off the troublesome jaywalking spots. They don't need ugly fences. They can get nice planters for the side of the road. Spadina Station would need a major rebuild. Probably a good idea to get some bidirectional cars if that ever happens. 

 

Maybe they should forget all this and just extend the Spadina subway south to Queen to meet up with OL. The Yonge Line can end at St George. PROBLEM SOLVED!

[Turtle]

9 hours ago, Xtrazsteve said:

They can improve speed further if the TTC upgrade the special works to modern switches and ditch those stop and proceed rules. Then fence off the troublesome jaywalking spots. They don't need ugly fences.

I don't think they would completely get rid of stop check and go with double pointed switches. You would still have to do it in the winter when the switches are covered with snow, or any time the switch is covered by water. They would keep the less than 10km/h rule through them, and the up trip would still have to yield to the down trip. Once a safety rule is in place, it doesn't magically go away with newer equipment. You would still get debris, snow, and ice build up in switches, so instead of having to clear one blade, you need to clear two.

 

Build a fence, people will hop over it or break a hole in it.  A water cannon installed on the roof of all streetcars would be more effective.

[Tom1122]

Please pardon me if this isn't the right thread, but this question is streetcar related.

I know former A-7 class PCC 4412 was used as a cafe in Scarborough called the "Jolly Trolley" for a number of years before going to a camp near Kitchener.

Two questions:

1. Does the car still exist in 2021?

2. What is the name of the camp?

[Cityflyer]

Looks like they'll be rebuilding some of the tracks on Adelaide Street via York Street and adding a connection at Queen St/York St.

Tracks already exist in Adelaide in most of the sections between York and Church but I guess they will put new tracks in as those tracks haven't been used for many years?

Metrolinx releases detour plans to keep people moving during Ontario Line Queen Street construction | Metrolinx News

This also brings the question of why they didn't do this for Osgoode Stn? Are there enough room there that they don't have to close off Queen St W?

[Articulated]

55 minutes ago, Cityflyer said:

Looks like they'll be rebuilding some of the tracks on Adelaide Street via York Street and adding a connection at Queen St/York St.

Tracks already exist in Adelaide in most of the sections between York and Church but I guess they will put new tracks in as those tracks haven't been used for many years?

Metrolinx releases detour plans to keep people moving during Ontario Line Queen Street construction | Metrolinx News

This also brings the question of why they didn't do this for Osgoode Stn? Are there enough room there that they don't have to close off Queen St W?

There's enough "vacant" (at least in Metrolinx's eyes) land around Osgoode Station for items like access ramps and construction staging areas, including the median of University Avenue and the Osgoode Hall lands, despite the protected heritage status of the park.

At Yonge/Queen, every square inch of land surrounding the road right-of-way is occupied by high-rise buildings, and both Yonge Street and Queen Street are narrow 4-lane roads, without the expansive median seen on University; therefore, the only way (again, according to Metrolinx) to access the underground is to go down through the roadway.

[Wayside Observer]

On 8/11/2021 at 10:34 PM, Turtle said:

 

Increasing acceleration rates will not help on Spadina. What slows Spadina down are all the safety rules that have to be followed, really poorly timed lights, long waits on reds because of left turn cycles, not enough time on a green for two streetcars to pass through on the same green light unless the ttc rules are bent (down trip has priority in trackwork that could create a collision if something goes wrong, like on College/Spadina on Sunday), having to travel less than 15km/h under troffs, 20km/h limit south of Dundas to Sullivan because of jaywalker fatalities, double stopping because of far side stops on red lights, ...

 

Also the LFLRVs really suck in curves, or to be more specific any changes in direction, those things will throw people out of the seats in the rear module if you go too fast. Comfortable speed entering and leaving Spadina circle is around 12-15km/h, once the whole streetcar is in the curve, it can smoothly go through a little faster but watch out for the next change in direction. Really violent cars if they aren't operated properly. Of course, nobody likes to hear a screeching streetcar every few minutes, so outdoor loops (stations, turnbacks) are limited to 5km/h in rail screech season instead of the normal 10km/h. All of Spadina tunnel is limited to 10km/h because of overhead issues - sagging overhead, bouncing pantos.

 

So many intersections with trackwork that has to be travelled through at no more than 10km/h with one or two stop check and go as well. College, Dundas, Queen, Adelaide, King, Queens Quay and Spadina, as well as the switches for Spadina loop. Then there is the tunnel to Ferry Docks (15km/h under troff, 10km/h on the curve, stop for the pedestrian crosswalk, then 10km/h the rest of the way in the station if nobody is crossing). Union loop is limited to 5km/h. Can't forget about the poor design of the row on Queens Quay, or the failure to anticipate people being people, so anywhere the tracks are beside the bike path, no more than 30km/h.

I was thinking purely from a technological perspective about whether it'd be possible to turn up the performance on an LFLRV.  Operationally, you're completely right, that's another matter that's dictated by a lot of stuff external to the streetcar itself.

I've been thinking about how the LFLRV cars can be a severely violent ride and I think a lot of it comes down to how they're laid out.  Effectively, what you have are three single truck cars, and single truck streetcars have always been known for being rough, that are joined together with two floating sections carred in between.  Sure, it's got all the modern styling, the air conditioning, LED lighting, the low floor, the accessibility stuff, the dot matrix signs, the text to speech announcements that sound like it's got marbles in its mouth, but what it boils down to are two floating sections of car body being carried in between three single truck Birney cars and it sure rides like it.

[John Oke]

4 hours ago, Cityflyer said:

Tracks already exist in Adelaide in most of the sections between York and Church but I guess they will put new tracks in as those tracks haven't been used for many years?

I believe they where abandoned sometime in the 1960’s 

[Wayside Observer]

4 hours ago, John Oke said:

I believe they where abandoned sometime in the 1960’s 

Does anyone remember what the exact routing of the 1980s tour tram was?  I could've sworn it used some of the one way street track on Adeliade while it was still usable but I could be completely mistaken.  In all honesty, I was enjoying the ride on the Peter Witt without paying too much attention to the details of the routing.

[Turtle]

8 hours ago, Wayside Observer said:

I was thinking purely from a technological perspective about whether it'd be possible to turn up the performance on an LFLRV. 

Maybe we'll see what this family of cars can do when they open the Eglinton lrt. I didn't notice anything different with the acceleration when I rode the Waterloo Ion cars

[smallspy]

18 hours ago, John Oke said:

I believe they where abandoned sometime in the 1960’s 

 

The "wrong way" trackage on Richmond, Adelaide, York and Wellington (as well as the one block on Church) was decommissioned when the streets were converted to one-way in or around 1958. But as much of the track there was in decent shape at that time - and not frequently used since - much of it has existed in situ until relatively recently.

 

14 hours ago, Wayside Observer said:

Does anyone remember what the exact routing of the 1980s tour tram was?  I could've sworn it used some of the one way street track on Adeliade while it was still usable but I could be completely mistaken.  In all honesty, I was enjoying the ride on the Peter Witt without paying too much attention to the details of the routing.

I can't remember the route of the Tour Tram, but that trackage was still useable throughout the 1980s. It wasn't until the late 1990s - 1997, I think? It was a year or two before Charlotte Loop opened - that the short section of track was removed near University and rendered that section unusable. From what I remember, another short section around Yonge was removed in the early 2000s before that section was rebuilt later that decade, and the intersection at York was rebuilt - without any east-west tracks - around 2013.

 

Dan

[Wayside Observer]

6 minutes ago, smallspy said:

I can't remember the route of the Tour Tram, but that trackage was still useable throughout the 1980s. It wasn't until the late 1990s - 1997, I think? It was a year or two before Charlotte Loop opened - that the short section of track was removed near University and rendered that section unusable. From what I remember, another short section around Yonge was removed in the early 2000s before that section was rebuilt later that decade, and the intersection at York was rebuilt - without any east-west tracks - around 2013.

That's pretty much my recollection of it too.  That track was useable and used through the 1980s and well into the 90s, at least the first half of the decade.

I went looking and couldn't find much information about the 1980s version of the tour tram and no routing details.  Once the TTC kiboshed the Peter Witt cars and the 2424 and 2894 went back to HCRR, they repainted the lower half of an HRB PCC to make it presentable for tour tram service and that got used briefly before the whole thing shut down for good.  There was also that brief fling (one summer only, I think) in the early 2000s with Toronto Tours chartering a PCC for a daily tour as well.

It's been a very intermittent on again, off again thing, mostly off again, that's never been documented very well.

13 hours ago, Turtle said:

Maybe we'll see what this family of cars can do when they open the Eglinton lrt. I didn't notice anything different with the acceleration when I rode the Waterloo Ion cars

I rode it several months after it opened and later read that some part of the signalling system that sounded like an ATP system wasn't functioning which meant a lower than normal speed limitation on some parts of their line.  When I read that after I rode it, it made me wonder how severely they were keeping the throttle in check on the sections of line where they should be able to really move it.  80 km/hr down to 60 km/hr is what I think I read so a 25% speed limit reduction means they wouldn't have to lean so hard into the high acceleration and braking rates.  I haven't been back since so I don't know if it's changed.

Eglinton is going to be interesting because that line is going to have ATO on the underground sections and everywhere else in the world, ATO has been used to maximize performance, so hopefully we get to see what the cars are capable of.  This is of course assuming Metrolinx doesn't turn it into the LRT version of Driving Miss Daisy.

[John Oke]

1 hour ago, smallspy said:

The "wrong way" trackage on Richmond, Adelaide, York and Wellington (as well as the one block on Church) was decommissioned when the streets were converted to one-way in or around 1958. But as much of the track there was in decent shape at that time - and not frequently used since - much of it has existed in situ until relatively recently

When did they start using concrete instead of cobblestone inlays for in between the rails? As on Adelaide the abandoned trackage has concrete there instead of cobblestones 

[smallspy]

22 hours ago, John Oke said:

When did they start using concrete instead of cobblestone inlays for in between the rails? As on Adelaide the abandoned trackage has concrete there instead of cobblestones 

I've never been able to figure out a date of the change from cobblestone to poured concrete. I suspect that one of guys who have been following the streetcar system for longer than I - Rob Lubinski or Steve Munro immediately come to mind - would know the answer.

 

23 hours ago, Wayside Observer said:

Eglinton is going to be interesting because that line is going to have ATO on the underground sections and everywhere else in the world, ATO has been used to maximize performance, so hopefully we get to see what the cars are capable of.

That's not quite true unfortunately.

 

Virtually all modern ATO systems are usually programmed with an acceleration curve and max speed a little bit below their absolute maximum. This is done for a number of reasons, but one of the lesser ones is to allow for a "catch-up" mode, where a single train (or more, if necessary) can operate in an enhanced mode to make up time versus the schedule.

 

While there is no doubt that the system will run quite quickly while the cars are underground, only in certain and limited circumstances will they be able to achieve the actual maximum performance of the equipment.

 

Dan

[Ed T.]

3 hours ago, smallspy said:

I've never been able to figure out a date of the change from cobblestone to poured concrete. I suspect that one of guys who have been following the streetcar system for longer than I - Rob Lubinski or Steve Munro immediately come to mind - would know the answer.

It was no later than the early 1970s. Rogers Road had a section of concrete track between Old Weston and Keele, and that route was abandoned in 1974. The track lasted an amazing length of time despite the heavy bus and truck traffic, possibly into the early 2000s.

[smallspy]

20 hours ago, Ed T. said:

It was no later than the early 1970s. Rogers Road had a section of concrete track between Old Weston and Keele, and that route was abandoned in 1974. The track lasted an amazing length of time despite the heavy bus and truck traffic, possibly into the early 2000s.

By that same token it would have been before 1958, because most of the trackage that was abandoned when York, Wellington, Richmond and Adelaide were one-way'd was poured in concrete.

 

But again, I don't have an exact date. It would be best to ask one of those two.

Dan

[T3G]

In the early days of this thread, the following photo was shared to the thread, with the accompanying caption, which was subsequently stated as having a lot of information that didn't make sense or was impossible (I would quote, but I don't want to unnecessarily ping people, the discussion is at the bottom of page 10 from June 2007).

High Voltage Streetcar - On the way home from The Horseshoe tonight, our TTC streetcar malfunctioned. The driver says that the car started accelerating uncontrollably. He put on the emergency brake, but it didn't stop the car so he pushed the "red button". Some strange noises occurred and then the power cable above the streetcar broke and fell down onto the streetcar. The wires started showering the car in massive amounts of electrical sparks. It was incredible the amount of light generated. They actually increased for the first few seconds and then as the wires fell to the ground. Once the sparks stopped, we were not allowed off the car. The car had actually run over the high voltage cable causing the car to be charged. The police arrived within seconds and setup a barrier, and TTC vehicles were on the scene within minutes. We were told to not touch metal and keep in our seats (which were, as you may know, made out of metal). We had to wait for the TTC cable repair truck to arrive, and once it did the crew cut the wire and discharged the car, and we were all let out the front doors.

Would anyone happen to remember what exactly happened here, or at least have any theories as to what? The part about the car accelerating uncontrollably is the first thing that sets off alarm bells as, if my information is correct, these cars were supposed to be designed to be failsafe so that this exact thing couldn't happen.

[Wayside Observer]

1 hour ago, PCC Guy said:

In the early days of this thread, the following photo was shared to the thread, with the accompanying caption, which was subsequently stated as having a lot of information that didn't make sense or was impossible (I would quote, but I don't want to unnecessarily ping people, the discussion is at the bottom of page 10 from June 2007).

 

 

Would anyone happen to remember what exactly happened here, or at least have any theories as to what? The part about the car accelerating uncontrollably is the first thing that sets off alarm bells as, if my information is correct, these cars were supposed to be designed to be failsafe so that this exact thing couldn't happen.

I read the comments below the picture on Flickr and groaned.

Anyways, going with the description since I have no memory of this incident, it sounds like there are two things which might be related.  Let's pick it apart:

The part about overhead getting torn down with tons of sparks, strange noises, and safety concern with everyone being required to stay on board the streetcar until it's de-energized is believable.  That's pretty much par for the course for a pole or pantograph mishap where the wire's gotten torn down.

The uncontrollable acceleration part is the more interesting half.  If the ALRV was having uncontrolled acceleration problems and went through some special work too fast, that could have been what caused the pole mishap that brought the overhead wire down, so that part's believable as well, and it's where also the two issues of sudden acceleration and the downed wires meet.

The cause of the uncontrolled acceleration's going to be the more difficult part to unravel and be a lot more speculative.  If it was acceleration and not a surge of slam on to full power, it doesn't sound like the pass elements in the chopper short circuited and caused 600V to be thrown directly onto the motors without any duty cycle control, so I think we can we can strike some sort of power side failure off the list of prime suspects.  If the car was accelerating and not responding to the brake pedal including pushing it down to the floor for emergency, my prime suspect would be some kind of control system problem that garbaged the operator inputs somewhere from the pedals on back and resulted in a bogus request for acceleration to be made to the traction and braking systems as if the driver was holding the power pedal down.  That's the perspective I'd start troubleshooting from once it's back in the shop and both powered trucks are cut out so the car doesn't try to take off while being checked out.  Put some instrumentation on the input side of the control system in a couple of strategic places like the driver controls interfacing (aka where the pedal positions are brought in) and outputs to the traction chopper and pneumatic brake system, start the car up, put the reverer in forward and see if acceleration gets requested even when the operator controls aren't calling for it especially with brake pedal down.

You know what would be really interesting to know?  Did the operator shove the deadman pedal down to the floor or let it up and the ALRV not respond to it leaving the big red button as the only thing that stopped the car?  Or did the operator keep the deadman in the operating position and immediately mash the big red button?

1 hour ago, PCC Guy said:

if my information is correct, these cars were supposed to be designed to be failsafe so that this exact thing couldn't happen.

The brakes over power design feature started on the PCC car.  What it means and what it can and can't do is something that's widely misunderstood.  What it means is that the default state is braking unless power is specifically called for under normal circumstances.  With that in place, it does improve the odds that if something goes wrong, the brakes will still work.  It doesn't guarantee that brake failures will never happen and it can't guarantee that the brakes won't be lost in an equipment failure/malfunction especially if it's serious.

A lot of people think it means "you always have brakes" when that isn't true.  Right before the end of the world, I was at a trolley museum and I asked about a PCC car and they told me that it kept bailing out and needed to be rewired because the insulation had gotten old and deteriorated and was falling off the wires.  Whenever they replaced a section that faulted and got the car running again, it would work for a while until another bit of insulation fell off and it developed another fault, so they've parked it until the can rewire it.  I mentioned it's a good thing they don't have any hills on their line because the wildcard possibility of losing the brakes if it's deteriorated that badly is kind of scary and was told that on PCC cars, braking takes precedence over power so you always have brakes.  My reply was that while this was true, it didn't preclude equipment damage from a grounded/shorting cable with bad insulation taking out part of the traction circuit (no dynamic braking) and damaging the low voltage side of things (no track brakes and in this case General Electric = no drum brakes if the low voltage goes out).  You're totally at the mercy of what went bad, how bad, where it went bad, and what other stuff did it affect when a seriously bad fault happens so no, braking isn't necessarily guaranteed when a cable shorts out, burns open and one or both ends land on something else.  It's desirable and commendable to make things as failsafe as possible, but it's impossible to provide a guaranteed outcome to any and all possible fault conditions that could ever happen.

[T3G]

1 hour ago, Wayside Observer said:

My reply was that while this was true, it didn't preclude equipment damage from a grounded/shorting cable with bad insulation taking out part of the traction circuit (no dynamic braking) and damaging the low voltage side of things (no track brakes and in this case General Electric = no drum brakes if the low voltage goes out).

I've heard of a thing exactly like this happening in Bratislava in the 1990s, all onboard power died and the car was at the mercy of the drum brakes being able to stop it from speed. They did, but not before the car ran away and nearly collided with the one ahead of it. The driver blamed it on bad maintenance of the brakes in that circumstance, though, and seemed confident that were they in good shape the runaway could've been prevented (that, and if the track speed had been set to such that a car with no dynamic or track brakes would be able to be safely brought to a stop using only drum brakes).

Were there any alterations made to the braking systems on the CLRV or Flexitys (perhaps ones that come with their own set of risks?), or is this exact problem a possibility on those cars too?

Scary to think what might have happened if that ALRV had run out of control.

[smallspy]

20 hours ago, Wayside Observer said:

The cause of the uncontrolled acceleration's going to be the more difficult part to unravel and be a lot more speculative.  If it was acceleration and not a surge of slam on to full power, it doesn't sound like the pass elements in the chopper short circuited and caused 600V to be thrown directly onto the motors without any duty cycle control, so I think we can we can strike some sort of power side failure off the list of prime suspects.  If the car was accelerating and not responding to the brake pedal including pushing it down to the floor for emergency, my prime suspect would be some kind of control system problem that garbaged the operator inputs somewhere from the pedals on back and resulted in a bogus request for acceleration to be made to the traction and braking systems as if the driver was holding the power pedal down.  That's the perspective I'd start troubleshooting from once it's back in the shop and both powered trucks are cut out so the car doesn't try to take off while being checked out.  Put some instrumentation on the input side of the control system in a couple of strategic places like the driver controls interfacing (aka where the pedal positions are brought in) and outputs to the traction chopper and pneumatic brake system, start the car up, put the reverer in forward and see if acceleration gets requested even when the operator controls aren't calling for it especially with brake pedal down.

One other thing to possibly muddy the waters....

 

The various types of power semiconductors can fail into an "on" state in limited circumstances. There are a number of videos on the interwebs about this, including several by two well known Canuckistanian YouTubers. Not to say that with any certainty that happened in this situation, but something to consider.

 

Dan

[Wayside Observer]

5 hours ago, smallspy said:

One other thing to possibly muddy the waters....

 

The various types of power semiconductors can fail into an "on" state in limited circumstances. There are a number of videos on the interwebs about this, including several by two well known Canuckistanian YouTubers. Not to say that with any certainty that happened in this situation, but something to consider.

 

Dan

Yes, actually I might not have phrased it in a way that was immediately recognizable but I covered that possibility along with the reasoning why I didn't think it was likely based on the description (assuming the description's accurate):

On 10/8/2021 at 12:04 PM, Wayside Observer said:

The cause of the uncontrolled acceleration's going to be the more difficult part to unravel and be a lot more speculative.  If it was acceleration and not a surge of slam on to full power, it doesn't sound like the pass elements in the chopper short circuited and caused 600V to be thrown directly onto the motors without any duty cycle control, so I think we can we can strike some sort of power side failure off the list of prime suspects.

Another reason why I don't think it's likely is that even if the thyristors in the chopper failed shorted, power would be removed from the traction motors by the line switch opening up if the control system had stopped requesting acceleration.  The line switch clearly didn't open up to cut the motor feed until the operator pushed the big red button on the dashboard so it mustn't have been responding to the driving control inputs.

Apparently there was quite a debate in the 1970s when the Boeing LRVs were being designed and Garrett (Boeing, CLRV) originally proposed a design that didn't include a traditional line switch because they felt it wasn't needed with the way semiconductors have a distinct off state but the MBTA insisted on a traditional line switch be included because they weren't convinced that the possibility of a power semiconductor failing shorted on was low enough to be safe.  Consequently, the Boeings, ALRVs, CLRVs, and pretty much everything else built to this day no matter how much or what type of electronics in the propulsion package, all have a traditional line switch ahead of them.

Edit with the benefit of a hot shower, breakfast and coffee:  I’d have to agree after a bit more thinking that the original proposal to leave the line switch out on the equipment Garrett was preparing for the Boeing LRV would be a very risky proposition indeed since you wouldn’t need to have a gross semiconductor failure with the pass elements failing shorted to have a full power runaway without a line switch to stop it.  Any malfunction causing the commutation circuit not to fire would leave the main Thyristors switched on even though totally they’re totally undamaged.  They’d just sit there happily switched on after an incoming gate pulse kicks them into conduction and if the commutation circuit doesn’t fire, no way to get the traction current back down under their latching threshold to get them to turn off again.

Anyhow, if everything works right in a chopper control, the pass elements cycle whether they’re a semiconductor class like GTO Thyristors or IGBT that can switch themselves off or regular Thyristors that require external force commutation to switch off and they switch off quietly and then the line switch opens after the semiconductors have already cut the power.  If they don’t, the line switch opens and breaks the circuit with a bang and a flash pushed down the arc chute by the blowout coil the old fashioned way we’re all familiar with on PCCs and older.  And that clearly didn’t happen with this ALRV because it kept on trucking until the big red button got mashed down.

[Wayside Observer]

On 10/8/2021 at 1:41 PM, PCC Guy said:

I've heard of a thing exactly like this happening in Bratislava in the 1990s, all onboard power died and the car was at the mercy of the drum brakes being able to stop it from speed. They did, but not before the car ran away and nearly collided with the one ahead of it. The driver blamed it on bad maintenance of the brakes in that circumstance, though, and seemed confident that were they in good shape the runaway could've been prevented (that, and if the track speed had been set to such that a car with no dynamic or track brakes would be able to be safely brought to a stop using only drum brakes).

Were there any alterations made to the braking systems on the CLRV or Flexitys (perhaps ones that come with their own set of risks?), or is this exact problem a possibility on those cars too?

Scary to think what might have happened if that ALRV had run out of control.

From what happened there, it sounds like the whole car was in pretty sad shape, not just the drum brakes.

Drum brakes on a PCC car are really intended to bring an all electric from ~1 MPH to a full stop and hold it in place.  They can, they were designed to be able to stop one from speed in a dire emergency but it's really hard on them.  I remember reading about the development of the all electric PCC and ERPCC/TRC considered the hills in Pittsburgh the worst case scenario and stopping and holding a fully loaded PCC on the worst of those was the design criteria.  Apparently there was some concern during development that tightening the drum brakes up enough to do that when they applied would cause a nasty lurch as they bound up right as the wheels stopped turning the way typical wheel tread friction brakes do (ie. air cars) but when they tested it, they discovered that the coefficients of static and dynamic friction with the brake lining materials were very close so it was smooth right to a full stop which solved the problem nicely so GE and Westinghouse went into production with it.

The real achillies heel with PCC drum brakes is that they were never self adjusting.  That was one of the items on the Transit Research Corporation's to-do list but was never gotten to before streetcar R & D wound down in North America.  The problem that's inherent to this is that on any given car, once they're adjusted during servicing, the drum brakes are in a constant state of getting worse as the car gets run and the brakes are used and wear because they don't automatically adjust to reflect that wear until the next time it's cyced through the shop for its next servicing and they're manually adjusted again.

Add a few emergency stops from anything more than a walking pace where all the brakes get applied at once, stop and go traffic with lots of stops to a standstill, anything else that hurries up wear and/or the next servicing not happening promptly and they can definitely get crappy.  PCC drum brakes used to vary from car to car all the way from a good prompt stop with a little bit of an authoritative bump at the end to a slow walking pace where you almost start to wonder if it's going to grab and stop for a moment or two before it does, to crummy long stops on level ground and not really being able to hold the car on average hills.  Maintenance makes a big difference because it's the only adjustment they get as they wear.

As I said, that Bratislava runaway car sounds like it was in pretty sad shape in general between the malfunction and weak drum brakes, and the operator's right, if the brakes were in good shape, it would've stopped a lot sooner.  When you think about it, if you have to depend on PCC drum brakes to get the car stopped, the best case scenario is to have to do it the day after it comes out of a servicing when they're in close adjustment vs. the day before getting serviced when the wear is at maximum before being adjusted again.  Throw in some deferred maintenance and it only gets worse.

Jeez, thinking about this, I can almost smell burning drums now...

[Ed T.]

A couple of random experiences with TTC's PCCs.

I was on a PCC eastbound on Queen east of downtown where it seemed that we had either full power or full braking. The operator said "the motor is kicking back" or something similar. This being the good old days, around 1980, the car didn't go out of service until Russel. And we got a ride into the yard on the ladder track, which was quite bumpy. I think that's my only ride through ladder tracks in a TTC yard.

Also circa 1980, I believe 4302--it was a 4300 series for sure--lost its brakes westbound on Howard Park, so it T-boned a northbound PCC on Roncesvalles, 4417 is what I think it was, whose rear end then derailed and sideswiped a southbound CLRV. I did not see this happen, but I sure saw the results. Again, someone said that the A6 cars had brake failure issues.

[T3G]

In the winter, does the TTC have to deal with concerns of too many streetcars leaving the yard for service with the heating on straining the power supply to the yard? If so, how do they deal with this?