Postby Joseph Frank1 » Wed Jan 17, 2018 12:32 pm
Hello Healey
Yes, in all cases with streetcars (trolleys) using OVERHEAD WIRE for power collection while running under EL's, yes, the wire was strung under the EL's. Usually it (the wire) ran in a wooden channel shallow conduit which was anchored by steel brackets and beams to the underside El structure deckwork above. The trolley wire was attached with hangers to the center-underside of the top wooden plank of the channel.
On much higher EL Structures, like some in NY City, Boston (when they had EL's) and Chicago, the span wires to support the hangers and trolley wires, were anchored to the parallel EL Columns using insulators to insulate the span wire from the cable or bracket that attached the span wires to the El columns. There was no need for the protector channel in those specific circumstances.
The reason for the wooden "protector channels" under standard and low height El structures (and just similarly when going under steel railroad track overpass bridges) was to protect a de-wiring trolley pole from springing upward and slamming, clattering, against the underside of the bridge or EL structure steelwork, thus damaging or worse, breaking the pole. Also to protect a de-wired pole that possibly had its pole sliding against the SIDE of the "hot" trolley wire and thus having its 600 volt (positive) DC energized trolley shoe or harp "grounding" itself in some flashing pyrotechnics, against the grounded (negative) Elevated structure steel work.
City ordinances early in Manhattan when horsecars were to be replaced by "streetcars" demanded that NO TROLLEY WIRE BE USED over the streets. Early "horseless" Streetcars in Manhattan operated like San Francisco Cable Cars, by underground cables in a slot rail between the running rails. The other Boroughs of NYC were exempt from this rule as they were then very rural anyway.
That is what you see in early Bowery photos along the El there. As I notice NO THIRD RAILS yet on the EL structures, the streetcar was still running by underground slot-cable at that time...and the EL trains powered by Forney Steam Locos hauling the El trains. By the way, the pointed-roof bank building seen is still there. this view is looking northwest across the Bowery to the then 2 separate tracks of the EL over the sidewalks , just north of Grand Street and the original Grand Street two separate local stations on the EL. By 1914-15 an entirely newly built 3 track EL structure with twin-island-platform express stations - was built over the center of the Bowery - replacing the later closed and demolished original two separate lines and their stations.
Later by 1900 or so, the conduit for the cable was reorganized to have an INSULATED Positive rail and a negative rail side by side under the slot. A special Slot-shoe with contacts on each side made contact under the pavement with these power and return rails. The running rails were not involved electrically at all for any return ground circuit. this is the way Manhattan streetcars ran until their demise gradually, route by route, between 1930's and 1947. And between 1900 and 1903, all the 4 Manhattan El's were electrified.
regards - Joe F