• trolley wires

  • General discussion about fallen trolley and interurban lines in North America, past and present.
General discussion about fallen trolley and interurban lines in North America, past and present.

Moderator: Aa3rt

  by JimBoylan
 
Disney Guy wrote:Does anyone have historical information on how a railroad installed catenary for pantographs if it decided to electrify a line that crossed a street with trackless trolley operation and mesh wire guards in place over the trolley wires? Or for that matter vice versa.
The most extreme example was in 1934 when the Pennsylvania RR electrified its crossing of the pre-existing Washington, Baltimore & Annapolis Electric RR. The PRR paid to alter the lower trolley wire so that 3 rigid and well supported sections of it per trolley track could be rotated 90 degrees to clear the pantographs when a PRR train crossed on one of its double tracks. You might say that the trolley pole ran UNDER 3 swing drawbridges in a row to cross UNDER the catenary. The drawbridges had to be opened to allow a pantograph to pass. Since this crossing was also an interlocking, wire guards weren't absolutely necessary. Signals couldn't be cleared for a collision while a stalled trolley car was on the track circuit in the crossing.
Here's a photo of how it was done in Philadelphia in a simpler manner:
http://www.davesrailpix.com/phila/htm/bvph331.htm
Willow Grove and Norristown, Pa., and South Chicago, Ill., also had this type of crossing. In all the cases I can remember, the trolley wire came before the railroad electrified, although in many cases, the railroad track was first of all.
One of the new Alberta, Canada subway-surface light rail lines that uses pantographs has a grade crossing near the portal with a trackless trolley line. It looks complicated.

  by 3rdrail
 
Probably the major problem to overcome would be avoiding the pan to bridge both positive and negative of the trolley coach wire only two-feet apart, so a 90 degree angle would probably be the way to go.

  by Disney Guy
 
Thanks.

I also was thinking of interlocking, which would eliminate the need for mesh trolley guards but would require that train be prepared to stop at the road crossing.

San Francisco also has shared pantograph and pole overhead intersections and at some locations a pantograph shoe does not touch either trackless trolley contact wire even with a non-90 degree angle.