The "All American Five", & more dangers!!

[Gyro]

It used to be interesting to look at the dates on the brass door sills in the tube trains, the older lines like the Northern. Many of them were early 1920s and still going strong (this was back in the '80s mind you). The bodies were original but of course there was regular replacement and renovation of all of the running gear.

A lot of these underground / suburban DC systems were specifically designed for fast acceleration and deceleration.

[vk6zgo]

It used to be interesting to look at the dates on the brass door sills in the tube trains, the older lines like the Northern. Many of them were early 1920s and still going strong (this was back in the '80s mind you). The bodies were original but of course there was regular replacement and renovation of all of the running gear.

A lot of these underground / suburban DC systems were specifically designed for fast acceleration and deceleration.

I used to love the "pentagon? shaped" lift in one of the tube stations.
It had an ancient recorded warning system that said "mind the doors" or something like that, in a rather "non human" voice.(that was before the advent of speech synthesisers, so I don't know why!)
I think it is closed now.

The Paris Metro back in 1974 had some really ancient carriages which looked like something out of a Wild West movie.
Those were otherwise normal, running on standard rails, but they also some mid/late 1950s "high tech" ones which had rubber tyres, with the rails basically just acting as guides & power feeds.

The suburban trains in Oz are 25kV ac for Brisbane, Adelaide & Perth, as they were later adopters of electric traction.
Sydney & Melbourne are stuck with 600 or 750v DC (can't remember which).

Back in 1971, Melbourne was still running the antique "Tait" cars, which shared the "Wild West" vibe with the Paris Metro cars mentioned previously.

[Homer J Simpson]

Hidden Killers of the Post-War Home

[Gromitt]

Similarly, the Swiss railways used 16-2/3 Hz, a subharmonic of 50 Hz.

Actually, germany, denmark and austria also use this system... It's a relict from the early 20th century, but it still works (some german powerplants even have dedicated 16 2/3Hz generators for that purpose). Btw, we even have a 400V three-phase suspension railway over here, i'd like to know which engineer envisioned this monstrosity (he was probably bored and decided he needed a new challenge).

Not Denmark. They use 25kV 50 Hz. Sweden and Norway uses 15kV 16 2/3 Hz.
 

[richard.cs]

Yes, 600V DC irrc. The London tube actually has a fourth (centre) rail. It returns current through this insulated rail, rather than the running rails, to prevent corrosion of surrounding metal structures, pipes, etc.

UK suburban 3rd rail systems are also 600V DC. They used to use mercury arc rectifiers, I don't know about these days.

In some areas (the south east basically) full sized trains on national rail are 700 V d.c. third rail, in most of the other electrified areas it's overhead 25 kV 50 Hz. Then there are lots of areas that only run diesel trains. It's a bit of a mess.

[Tepe]

Similarly, the Swiss railways used 16-2/3 Hz, a subharmonic of 50 Hz.

Actually, germany, denmark and austria also use this system... It's a relict from the early 20th century, but it still works (some german powerplants even have dedicated 16 2/3Hz generators for that purpose). Btw, we even have a 400V three-phase suspension railway over here, i'd like to know which engineer envisioned this monstrosity (he was probably bored and decided he needed a new challenge).

Not Denmark. They use 25kV 50 Hz. Sweden and Norway uses 15kV 16 2/3 Hz.

And Copenhagen S-trains use 1500V DC

[vk6zgo]

Yes, 600V DC irrc. The London tube actually has a fourth (centre) rail. It returns current through this insulated rail, rather than the running rails, to prevent corrosion of surrounding metal structures, pipes, etc.

UK suburban 3rd rail systems are also 600V DC. They used to use mercury arc rectifiers, I don't know about these days.

In some areas (the south east basically) full sized trains on national rail are 700 V d.c. third rail, in most of the other electrified areas it's overhead 25 kV 50 Hz. Then there are lots of areas that only run diesel trains. It's a bit of a mess.

Yeah, I remember when I lived in Southampton for nearly a year, back in 1971.

Some of the level crossings had an attendant full time, who closed a full gate, completely blocking acesss to the crossing when the rails were "hot", not just a boom,like I was used to from Oz.
Other trains into SOTON were diesels.

When I travelled further afield, I discovered a different mix, this time diesels & overhead cable pantograph types.

Years later, back home, when Perth WA was first being electrified, the bus I took to work used to cross the line near the city station.
When the lights went green we waited for a moment till a truck with a big excavator from the work site crossed.
They got their heights wrong, & hit the already activated overhead cables, causing a blinding flash, & eveything shut down.

We were still running diesels, so loss of 25kV didn't automatically shut them down, but it made all the lights red for that section.
Needless to say, I was late for work!

[richard.cs]

Yeah, I remember when I lived in Southampton for nearly a year, back in 1971.

Some of the level crossings had an attendant full time, who closed a full gate, completely blocking acesss to the crossing when the rails were "hot", not just a boom,like I was used to from Oz.
Other trains into SOTON were diesels.

I'm from Southampton. The manned level crossings are gone, the current approach is automated gates, basically booms with a hanging fence below it, and having the third rail stop a few metres short of the road from each direction. Quite likely some of the crossings have been replaced with bridges too.

[vk6zgo]

Yeah, I remember when I lived in Southampton for nearly a year, back in 1971.

Some of the level crossings had an attendant full time, who closed a full gate, completely blocking acesss to the crossing when the rails were "hot", not just a boom,like I was used to from Oz.
Other trains into SOTON were diesels.

I'm from Southampton. The manned level crossings are gone, the current approach is automated gates, basically booms with a hanging fence below it, and having the third rail stop a few metres short of the road from each direction. Quite likely some of the crossings have been replaced with bridges too.

I tried looking at SOTON with Google Earth a while back, & couldn't recognise a lot from the old days.

I finally found the railway station & the Bargate, but the latter looks insignificant compared to how it used to be------------ somehow "pushed off into a corner" & ignored.

My memories of places in the UK are, of course, suspended in time from the early '70s, & I was only there for a short time.
I can understand how people who lived their whole lives in that country, then migrated to another are shocked when they return for a visit after many years.

Of course, there have been huge changes here in Perth, WA over the same time period, but being here as they happened, I have become used to them.

All the suburban trains here were diesel railcars back then-------- we went electric in the mid/late 1980s.
As an old fart, it is hard to realise there are now adults in this city who have never known anything but electric trains.

[G7PSK]

I grew up in Cambridge UK during the 60's and there was still areas that were 240 volt DC. They were switching over gradually, the house e were in was changed over just a few days after we moved in from London, a tutor I had just ten minuets walk away house got changed over in 62, I went there in the early afternoon and there was no power and men all over her house changing things like parts on the cooker and sockets etc.

[25 CPS]

It used to be interesting to look at the dates on the brass door sills in the tube trains, the older lines like the Northern.

Agreed.  It was always interesting to look down and see who built the train and when.  To my mind, the British always made the best builder's plates.  It was educational doing that in the various places I grew up in back when a lot of cities still had old junks running on their public transportation systems.  I always loved the worst, oldest, most beat up stuff running because it was always the most interesting.

I have not seen a reference to this, but I believe train cars with sliding power contacts to DC feed (third rail or overhead wire) use capacitors on the vehicle to mitigate rough connection.

No.  No need, the inertia of the whole mechanical system that is a subway train is far better a filter than a bank of capacitors would be.  The exception is for equipment that has chopper controls and there's a smoothing filter on the output side of the chopper which is to clean up the square waveform output of the chopper, not filter current collector bounce.

The Chicago Transit Authority retired the last 6000 series ‘L’ cars in 1992, after 42 years of service.  IIRC, there were three forward settings on the speed lever:  resistor, series, and parallel (fastest).

Yes, normally those three power positions would be switching, series, and parallel as you mentioned but the CTA 6000 series cars and the 1-50 series cars which were single units with a cab at each end instead of a married pair were exceptions to the rule.  Those were basically repackaged PCC streetcars and those were permanently wired in parallel.  Westinghouse supplied the stuff on those cars and what the controller positions did was change the value of traction motor current being demanded by the limit relay and rheostatic controller, to control acceleration rate.  Eventually, or not so eventually depending on what position you stick the handle in on one of those, you get full speed no matter what vs. a traditional switching/series/parallel traction package does.

[Electro Detective]

Butting in with a quickie query:

Were the techs of yesteryear using AVOmeters and Simpsons etc for checking and confirming railway voltages 600v and beyond?

or were there specific tools for that?

Were there any high zappage risks even for cautious operators with the right gear and PPE?

and Danger Money rates that made it sort of worth it?

[jeffheath]

Say what you will about corvairs, but like AA5 radios were, they're cheap! They're the cheapest classic car there is other than all those bland moredoors.

[25 CPS]

Butting in with a quickie query:

Were the techs of yesteryear using AVOmeters and Simpsons etc for checking and confirming railway voltages 600v and beyond?

or were there specific tools for that?

Were there any high zappage risks even for cautious operators with the right gear and PPE?

and Danger Money rates that made it sort of worth it?

For checking the presence of 600 V in a is it there/is it not there way the quick, easy, and cheap way was with a 600 volt test light be it a string of 5 120 V bulbs in series or a dropper resistor feeding one or two bulbs.  This was less expensive than giving everyone meters, but yes, techs troubleshooting more complicated faults would use Simpsons, AVOs, Tripplets, that sort of thing when a test light wasn't suitable.

As far as the safety aspect goes, under normal circumstances, it's neither here nor there compared to a modern Fluke meter.  You still need to be careful of live electricity and if you slip up and touch something that's live by mistake, it doesn't really matter what kind of meter's hooked up to your probes, there's always the risk of getting zapped when you're working on live power equipment of any kind if you mess up.  I can't really speak to danger pay since I've only worked on streetcars at a handful of railway museums whenever they've asked for help with difficult electrical problems so that's strictly volunteer basis, but I have used my own Simpson 260s and Agilent U1641A insulation tester multimeter and an Agilent U1213A clamp meter when doing so and a couple of other people have Fluke DMMs.

[rsjsouza]

Were the techs of yesteryear using AVOmeters and Simpsons etc for checking and confirming railway voltages 600v and beyond?

600V?!? Pffft! A Triplett 630-NA was rated to 6kV! Pizz o' cake! 

[CatalinaWOW]

And remember attitudes toward HV weren't so fearful then.  Every radio had from  150V to 450V inside.  TVs had 15-35kV on the CRT.  A huge number of stores had 15-35kV transformers to power their neon signs.  Familiarity bred a certain contempt.

[TimFox]

Note that the Triplett meter had an extra input connection (unshrouded banana) for the 6000 V input.  I wonder if it used an external probe?

[rsjsouza]

Not according to its manual straight from "the source" (CIA)

https://www.cia.gov/library/readingroom/docs/CIA-RDP70B00584R000100220001-9.pdf

(the only mention of high voltage probes is coverinh 12kV and higher)

[calzap]

I owned and drove a Corvair for a few years.  My mom gave me the money to buy it from my dad, and he was selling it cheaply.  I really enjoyed it and the way it handled.   It was a medium sized car (for the time) with a relatively heavy opposed-six, air-cooled engine in the rear.  Main difference between it and other cars of the time was that you needed to be a little slower going into a corner, but could accelerate midway through it.  Start a corner too fast, and that heavy rear could swing around, wheels could lose their grip, and a spin would ensue.  Once you got the hang of it, it could be fun to go into a curve and let the momentum of the rear finish the steering.  I drove it on gravel roads, snow and ice without a problem.  It had great traction because the engine weight was over the driving wheels, which was unusual at the time.  I think accidents occurred because its handling was so different, and some folks couldn't adapt.

Biggest problem for me and caused me to get rid of it wasn't the location of the engine but another design feature.  It was a split block engine with the two halves bolted together with a gasket in between.  Eventually, the gasket started to deteriorate, which had two consequences.  First was oil leakage.  Second was more serious.  Recall that it was an air-cooled engine.  So to heat the cabin, air was circulated through a chamber attached to the engine.  When the main gasket started to fail, crankcase/exhaust gases started entering the heater chamber.  Not comfortable to drive in winter with the windows open to avoid asphyxiation.  Replacing the gasket was very expensive because the engine had to be pulled to do it.  So, I traded it to help buy a pickup.

Mike in California

[25 CPS]

And remember attitudes toward HV weren't so fearful then.  Every radio had from  150V to 450V inside.  TVs had 15-35kV on the CRT.  A huge number of stores had 15-35kV transformers to power their neon signs.  Familiarity bred a certain contempt.

To a degree; those high voltages were familiar but the lack of current delivery with those sources could definitely lead to contempt for sure because the output of those were measured in mA vs. thousands, potentially many thousands, of amps from a traction power substation that's available on the supply side buss bars inside a propulsion package in a streetcar or subway car.  A better comparison would be large industrial electrical distribution like 600 v three phase which is common in Canada or 480 v three phase common elsewhere with a similarly large current capability.

600V?!? Pffft! A Triplett 630-NA was rated to 6kV! Pizz o' cake! 

I've got a nice army surplus Bach-Simpson 635 that takes care of my 6 KV needs.  No problem there!