The power and freight equipment in the SP Packs are representative
of the era of the railroad when all the road locomotives(and most of
the yard power) used the classic SP light package. This era began when
the locomotives were built, and ended around 1991. Typically, SP
locomotives had both oscillating lights on the cab and static headlights on the hoods, and also the
red warning light(oscillating and static). By the early 90's, the static
headlight was the only remaining part of the original package on SP
power, and the classification lights had been plated over.