Why did the PRR buy the LIRR in 1900 and build its grandest station in the middle of New York City? The following is from the PRR's bulletin of August, 1910, announcing the opening of Pennsylvania Station in New York:
"It was the Company's plan to run its passenger trains into a centrally located station in the city of New York, instead of one on the western bank of the Hudson River; to give rapid transit from the residential sections of Long Island, and to offer Newark and other cities in New Jersey, direct and quick access to New York City, and to the resorts on Long Island beaches.... The Company desired to give to the Boroughs of Brooklyn and Queens, with their population of over 1,500,000, direct railroad connections to and from New England, Southern and Western States, and to provide freight facilities with similar connections in these Boroughs, with freight stations suitably located to develop their commercial interests."
The entire text of the booklet, along with a map, follows:
Major improvements -
and here are two maps by Bob Emery that show the old (dotted line) and new alignments.