from C B Fairchild, Street Railways , 1892 |
The drawing shows a cross-section of the 125th Street
cablecar track. Yes, there were cablecars in Manhattan once
(but not here on Broadway), in the 1890's. The same track
construction was applied to electric conduit track, so the
illustration will apply here.
The street surface is at the top of the diagram. At the right and
left top corners, we see the running rails for the streetcar's wheels:
unlike the simple capital I cross-section of railroad rails, these
have a shelf along the inner side to hold open a path for the wheel
flanges. In the center, we can make out the thin somewhat S shaped
cross sections of the two iron edges of the conduit slot. In the
photo, at one place the slot has become almost closed near a white
concrete patch signifying some post-streetcar roadwork. In service,
the slot had to be kept open between 5/8 and 3/4 inches by constant
inspection.
The diagram shows a cable grip coming from an unseen cable car down
to hold one of the two cables in Manhattan's unusual two-cable system
(the loose cable is below and right of the grip). In the conduit
system, the plough was smaller than the cable grip, which had to have
moving parts. For that reason I think the inside dimension of the
electric conduit was probably a bit smaller than this, but I'm not
sure it was very much smaller.
Most of that structure shown is cast iron. The dark area around
the conduit is concrete poured on site.
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