IHB SW1500's 1511 and 1524, along with "hump trailer" slug 477 shove a heavy train to the hump at Blue Island Yard in Riverdale. The SW1500's were built in 1967 and 1968, respectively. Slug 477 was built in 1949 as an IHB NW2, before being later rebuilt to what it is now. All three units see regular service, but the hump jobs lately have been handled mainly by the RPI RP15DF units and it's been said that the slugs may be headed for storage in the future. Changes...