SP5103 Wrote:
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> SP seemed to be hit and miss as to whether they
> ordered switchers with signal lights or not. They
> show up on some H12-44, SW8, S12, SW1200 and
> SW1200 units, becoming standard on the SW1500s.
> Presumably the earlier units were ordered with
> signal lights for their initial assignment to the
> LA Basin or Bay Area where street running and a
> multitude of crossings were common.

> snip <

> 4618-4621/1123-1126 (the last 4 within a order of
> 10) and 4622-4623/1127-1128 were ordered with
> signal lights.

Looks like you've been reading Strapac's Compendium. Caveat emptor!

Strapac's rosterbook info is often disproved by photos, including some that actually appear in his books. His listing for SW8's with signal lights is a good example. In his Compendium, he lists the units that you've quoted. Yet in his SPHD Vol. 16 EMD Diesel Switching Locomotives, there appears on page 47 a photo taken in mid-1953 at Tiburon of MUed 4613, 4616 and 4617 which clearly show Mars WR-816 signal lights on each unit. Other pictures of these units in the same book taken between mid-1954 and 1958 show that the lights had been removed by then. A photo of the 4614 also clearly shows where the front Mars light had been. So what happened to the Mars lights on these units? Hard to say for sure, but a good guess is that they were reapplied to SD7's.

To respond to your first statement, maybe I'm confused. None of the earliest switchers had signal lights. In fact, I can't think of any switchers that were ordered with signal lights until the fall of 1952.