regarding the last five words:

The contact wires in close proximity may be approaching a turnout; one will be straight and the other will turnoff with the siding.

Thus each tangent track away from a turnout has double contact wires for about a span; then the lines from the spur track are deadended at the next pole further away from the turnout. This last pole will have a down-guy to handle the horizontal load.

When visiting the cities with LRV OCS, sketch or photograph each property's "standards". You may find some variances. My preference was to minimize poles; making them heavier if necessary. On one property I've toured, the designers maximized the pole count by not expecting a pole to serve more than one purpose.

Experience was on Seattle's two-wire and single wire systems.

We design looking from above - then build looking from below.