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Pantograph vs. Trolley poles


Ian Blenk
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4 hours ago, Philou said:

 

I have a question relating to both tram and trolleybus overhead: How were the bronze hangers that were attached to the span wire (similar to those shown in the photo above) insulated? The blade holding the contact wire was fixed inside but if there was no insulation there would have been a direct short between live and neutral in the case of the trolleybus system as there was no other form of external insulation on the span wire prior to its attachment to the traction pole - but what at the actual interface between the contact wire hanger (?) and the span wire itself?

 

 

The insulation in tram/trolley overheads is/was achieved in two ways. The ears are insulated between the bit of lead that is hammered around the contact wire, and the bit of bronze that the support wires are tied to by a porcelain insulator, the lead bottom bit is threaded, and the bronze ear is hollow. The ear fits on the insulator which is bolted to the lead bit. The ears can be long of short, long for trolleypoles only (the ear hangs below the contact wire) or short so that pans/bow/trolleys can be used. Most of the overhead fittings at Crich come from Liverpool, who fitted their overhead for bows, even though they only every used poles.

 

Trolleybus wire needs double insulation between the two live wires and the poles (I'm not sure is tramway single wire needs the same or not?). Usually this is achieved by the first insulator being on the hangers (as above) and then another insulator on the span wires (this being a porcelain insulator that has holes at 90* to each other, the span wires going through one hole for the right side, the left side going through the other, so the porcelain is in tension between the two wires.

 

Andy G

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Trams can run on the same wire as trolleybuses if using poles. The bus uses two poles, the tram one and the track.

In Birmingham one single wire tram route was used for a trolley bus, route 7 to get to & from Washwood Heath Tram Depot where the trolley buses were stabled, the current return was a skate towed in one of the tramway rails.

The same method was used when a trolleybus needed to go to Kyotts Lake Road works, which was only wired for trams.

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Toronto had a couple of stretches where TBs and SCs shared wires. 

What I remember at one point is that the wires separated when they reached a cross street that they had to turn at. There was an electric frog in the wires that the trolleybus would activate (automatically) to turn it off the streetcar wire.

I don't remember the situation at St Clair station where the two shared a loop which had formerly been streetcars in both directions; the buses took over the eastern (short) end.

 

I have a suspicion that British frogs were controlled. (My only exposure was in the Covent Garden museum.)  N. A. Streetcar frogs were a solid casting and the shoe/wheel was dragged in the desired direction. There may have been an offset in the wire to encourage it to follow.  Trolley bus frogs (facing) were electrically turned. Two contacts were set so that if the bus were turning the poles would be offset and touch the pair at the same time. This caused movement in the frogs. As the poles passed through, they physically forced the frog back to straight position.  I have a page somewhere showing how to take a bus around a curve to get the best position for the frogs.

 

 

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Just stumbled across this interesting thread.

 

My Mrs, works for a department that among other things that have flashy blue lights on the top, looks after trains.  Trains here are either steam or trolley pole powered very old electrics.  I ride the Manx Electric Railway to her office in Douglas on Fridays in season, and we ride back together.  This Friday, unusually, one of the trailer cars that enable you to watch the trolley pole closely was in use and I rode that as the power car was full of blue-rinse tourists making a right racket.  I noted that to use a pantograph on the current (badoom-tish) overhead would be difficult, as it would need to have a head about eight feet wide to keep contact.  There are very sharp curves in places, and the wires really do vary in their positioning, at times a LONG way from the centre of the track.  There's also a lot of sag in the wires here that a panto may struggle to keep reliable contact without a lot of arcing.  The mountain railway uses bow collectors as trolley poles would blow ff the wire in some conditions.  It can get mighty windy up there!

 

911849903_P1000539(Medium).JPG.360b1437da257fc8ec881ffb3a170908.JPG

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An interesting observation, and raises the subject of the two types of trolley pole head.

Early trolley poles had a fixed head: the wheel can rotate on its axis but is fixed to the pole in all other directions. The MER, being a very early electric railway, has this arrangement. The wires are therefore laid out to minimise the angle of the trolley wheel relative the the wire (in plan view) and this means that on curves the geometry of the wires is not directly above the track, but usually offset slightly to keep the wheel aligned to the wire. The system is not ideal for bi-directional running but that's not a problem on the MER which is double-track.

16_howstrake_20110901

 

Many later tramway systems used swivel-head trolley poles where the wheel can pivot in plan view (yaw) relative to the pole. This reduces wear of the wheel and wire on curves and is better for bidirectional running, but requires a different geometry of wire positioning on curves. I think at one stage there was a proposal to convert the MER to swivel head operation, but the cost of realigning the wires on all the curves would have exceeded the savings in wear.

 

Pantograph systems usually have a significant tension in the OLE contact wire (and often a supporting catenary wire) to keep the contact wire as horizontal as possible. That is not necessary on a trolley pole system, and the upward pressure of the trolley pole springs can lift the wire significantly:

33_ballaragh_20110901 32_howstrake_20110901_2

 

I'll be visiting the island again later this month and I hope the weather is as kind as it was 10 years ago when I took these photos!

 

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7 hours ago, BR60103 said:

Toronto had a couple of stretches where TBs and SCs shared wires. 

What I remember at one point is that the wires separated when they reached a cross street that they had to turn at. There was an electric frog in the wires that the trolleybus would activate (automatically) to turn it off the streetcar wire.

I don't remember the situation at St Clair station where the two shared a loop which had formerly been streetcars in both directions; the buses took over the eastern (short) end.

 

I have a suspicion that British frogs were controlled. (My only exposure was in the Covent Garden museum.)  

 

I'm sure I've seen a Pathé type newsreel that showed a Linesman in the street pulling a handle to set the routes in the overhead. There was also a semi automated system that recognised if a Trolleybus was under power or coasting, and would set a route according. 

 

From memory the F line streetcars in San Francisco use a transponder so the Motorman can select a route, but this would be more for trackage rather than the overhead.

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17 hours ago, Philou said:

In response to the OP's original question, that I took to mean tram - tram overhead, I have never seen pantograph and trolley pole using the same contact wire. What I did see in Montreux (possibly Vevey) was a trolley bus (pole) - tram (pantograph) contact wire along the same route.

Afraid I can't help you there.  All I saw of Vevey was the inside of the Hôpital de la Providence where they had a priest waiting to ready me the last rites on arrival.  Understanding that would have delayed slightly my operation, my father said "Anglican", which resulted in my being visited in hospital by the CofE vicar of Montreux! 

 

It was the year we won the World Cup and I hung up my football boots - the two events not being related!

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The trolleybuses in Cardiff originally used the patent 'Callender' head that was bronze (or brass) that not only swivelled left/right along the axis of the pole but also 'nodded' to align with any imperfections or droop of the contact wire. They weighed a massive 8lbs and were tied to the pole by means of a cord should one be detached from the pole following a dewirement (as they did from time to time - cue the conductor taking the bamboo pole from under the 'bus and chasing the errant pole).

 

Due to the concerns of possible severe injury caused to the public, Mr Cununder the Transport Manager of the time, designed a lightweight head weighing in at about 2lbs. This head only had the horizontal swivel and no 'nodding'. By removing the 'nodding' action, dewirements were much reduced and there was no discernible extra usage of the carbon insert . The foundry of the Cardiff Corporation Transport undertaking were very adept at casting their own special fittings - heads, frogs, crossings etc.

 

Another Cardiff design was a very short presolenoid run up to the electrofrogs (just a few inches rather than a couple of feet) as it very much reduced the burning out of solenoids as did happen on other systems where the trolleybus may have been held up within the section and the frog held open. I happened to see the system work just the once and it was indeed very quick - really 'click-clack' and that was it. It is right to say that the 'bus had to be coasting or drawing power for the system to work (possibly using back EMF?).

 

Some overhead junctions that were very lightly used (short or return to depot only workings) were hand operated by the conductor (no linesmen for the trolleybuses - don't know if there were pointsmen for the trams though).

 

I really missed the trolleybuses whose demise were probably influenced by the motorbus lobby - all following London's lead. Cardiff's system was a youngster, less than 30years old (1942-1971), when it closed definitively.

 

They are however, bringing back trams, both street- and train-trams (search for Cardiff Metro on t'intertubes if interested).

 

Cheers,

 

Philip

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@Michael Hodgson I hope you made a full recovery.

 

It was around 1970 that I saw this particular overhead arrangement. I've just had a look on Streetview but there doesn't seem to be a tram line anymore where I thought I saw it. The trolleybuses are still running.

 

Cheers,

 

Philip

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Thanks for all the replies, I think I have created a monster.

 

I'm guessing the short answer to my question is 'No'

 

I've always had a soft spot for the Arrowhead branch of the Pacific Electric and wanted to build something similar, not necessarily P.E.R.  Looking at my stock I have an interurban car (Pantograph), Juice Jack (Trolley) and a Box Cab (Pantograph) I was kind or wondering if  I could run them without any modifications, But I guess I will have to put a panto on the Juice Jack as per North Sacramento. I won't be doing anything soon as I have Hallbankgate to finish and South Gallions to prepare for Workington show in November.

 

Thanks guys!

Ian B

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2 hours ago, Ian Blenk said:

Thanks for all the replies, I think I have created a monster.

 

I'm guessing the short answer to my question is 'No'

 

I've always had a soft spot for the Arrowhead branch of the Pacific Electric and wanted to build something similar, not necessarily P.E.R.  Looking at my stock I have an interurban car (Pantograph), Juice Jack (Trolley) and a Box Cab (Pantograph) I was kind or wondering if  I could run them without any modifications, But I guess I will have to put a panto on the Juice Jack as per North Sacramento. I won't be doing anything soon as I have Hallbankgate to finish and South Gallions to prepare for Workington show in November.

 

Thanks guys!

Ian B

 

Can you post photos of them please?

 

The Arrowhead branch would definitely have been trolley poles only, and closed quite early.

 

Another oddity are the handful of trolley pole equipped diesels, necessary to trip the crossing activation equipment mounted in the overhead. I've not seen a steam loco with one though, as SP trains were piloted by a PE electric.

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3 hours ago, Philou said:

I really missed the trolleybuses whose demise were probably influenced by the motorbus lobby - all following London's lead. Cardiff's system was a youngster, less than 30years old (1942-1971), when it closed definitively.

 

Cheers,

 

Philip

Birmingham were a earlyish adopter of Trolleybuses, starting in 1922.

However the system didn't grow much and was abandoned in 1951*  before the trams it was supposed to replace.

 

* This is just 2 years after Glasgow opened it's trolleybus system! (The last in the UK to open and the only one post war)

Glasgow lasted only 18 years to 1967 but grew to be moderately large.

 

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54 minutes ago, 298 said:

 

Can you post photos of them please?

 

The Arrowhead branch would definitely have been trolley poles only, and closed quite early.

 

Another oddity are the handful of trolley pole equipped diesels, necessary to trip the crossing activation equipment mounted in the overhead. I've not seen a steam loco with one though, as SP trains were piloted by a PE electric.

Yep Arrowhead was trolley only and as you say lost it's passenger service early on. Freight for Arrowhead water ran for a while longer with trolley fitted diesels, I was thinking of something similar, but different drawing inspiration from your modelling of the YVTC. There are quite a few snaps of PER diesels on line https://www.trains.com/ctr/railroads/fallen-flags/remembering-pacific-electric-railway-locomotives/

 

I will post some pics of my megre range of stock soon

 

Cheers

 

Ian B

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I'd forgotten about the water. I quickly googled it and Wikipedia stated the closure date was 1929.

 

I still have Wiley City in storage, but for my next YVT layout I'd probably model somewhere at the midpoint of a line to allow trains to run through the scene. The punters get to see a train running but with less faffing about with poles and simpler/more reliable overhead. 

 

Somewhere on my top ten layout list would be a similar Pacific Electric layout but with very much a 1930s SoCal art decor theme. Suydam could probably provide the stock but unfortunately I only have a Baldwin B and the body for an Electra Steeplecab. 

Edited by 298
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11 hours ago, Mol_PMB said:

An interesting observation, and raises the subject of the two types of trolley pole head.

Early trolley poles had a fixed head: the wheel can rotate on its axis but is fixed to the pole in all other directions. The MER, being a very early electric railway, has this arrangement. The wires are therefore laid out to minimise the angle of the trolley wheel relative the the wire (in plan view) and this means that on curves the geometry of the wires is not directly above the track, but usually offset slightly to keep the wheel aligned to the wire. The system is not ideal for bi-directional running but that's not a problem on the MER which is double-track.

16_howstrake_20110901

 

Many later tramway systems used swivel-head trolley poles where the wheel can pivot in plan view (yaw) relative to the pole. This reduces wear of the wheel and wire on curves and is better for bidirectional running, but requires a different geometry of wire positioning on curves. I think at one stage there was a proposal to convert the MER to swivel head operation, but the cost of realigning the wires on all the curves would have exceeded the savings in wear.

 

Pantograph systems usually have a significant tension in the OLE contact wire (and often a supporting catenary wire) to keep the contact wire as horizontal as possible. That is not necessary on a trolley pole system, and the upward pressure of the trolley pole springs can lift the wire significantly:

33_ballaragh_20110901 32_howstrake_20110901_2

 

I'll be visiting the island again later this month and I hope the weather is as kind as it was 10 years ago when I took these photos!

 

 

Some nice photos there!  Things have changed - 16 isn't green now - but 21 is!  33 is my favourite car, as the newest and most powerful (with 32) in the fleet.  Ratchet 14 has been out too.

 

Have a good visit!  Big timetable on the half term weekend.

 

20210801_103835.jpg.797dea6cdc5ee8726a808a4843a26c50.jpg

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Mr Marsbar's insulator is a section insulator to separate parts of the overheadthat have different supplies or that may have to be turned off for maintenance.  Toronto's have a sign "Pass under with contrller off."

Mol_PMB's photo is one of the new Toronto cars.

Another consideration of joint pole/pan operation is tensioning. Pantographs seem to require a more level wire than poles. This is often done by running the wire off and putting weights on it. The segments will run parallel for a distance with 2 wires. This creates a discontinuity for pole operation.

 

About 50 years ago I had a small trolley layout. I used Suydam's frogs (bent sheet brass) which had a curved side that pushed the pantograph below the wires and also guided the pole's shoe. I managed to run both pole equipped cars and a Fleischmann 4-wheel steeplecab.

 

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Track point operation: I think most N.A. systems used the power on/coast method for streetcars. Sometimes they might have to go under with both the throttle and the brakes on.

Toronto had the "Necessity Action" switch. There was a contact dangling by the wire about a car length before the switch. Pushing the NA button on the dash caused the point to be set for the diverging route. Not pushing the switch caused it to be set straight. There was a little knob on the side of the shoe that touched the contact.

 There was a variant called Self Restoring. The point had to be set by hand (big crowbar) but would be resored by the next car through the contact.

There was an addition on routes with MU trains. This would count poles and not allow the automatic restore unless all the poles had left the length.

If there was a puddle over the switch points it made quite a splash.

When TTC bought new cars that had different lengths, they had to abandon this system and brought in transponders that seemed to take years to debug.

 

(Apologies, but you've got me on one of my hobby horses.)

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14 hours ago, 298 said:

I'd forgotten about the water. I quickly googled it and Wikipedia stated the closure date was 1929.

 

I still have Wiley City in storage, but for my next YVT layout I'd probably model somewhere at the midpoint of a line to allow trains to run through the scene. The punters get to see a train running but with less faffing about with poles and simpler/more reliable overhead. 

 

Somewhere on my top ten layout list would be a similar Pacific Electric layout but with very much a 1930s SoCal art decor theme. Suydam could probably provide the stock but unfortunately I only have a Baldwin B and the body for an Electra Steeplecab. 

Do you know a good source of trolley poles?

Cheers

Ian

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