SELECT "system" FROM table_203_674 WHERE "name" = 'pennsylvania railroad'
was the pennsylvania railroad under the prr or the rf & p ?
CREATE TABLE table_203_674 (
    id number,
    "name" text,
    "mark" text,
    "system" text,
    "from" number,
    "to" number,
    "successor" text,
    "notes" text
)