Disneyland is 87 acres. The Magic Kingdom is 107 acres. Even if you include 12 acres for Star Wars land(which doesn't take up all new land...some is old property being repurposed: Rivers of America), that only brings it to 99 acres.
There is way more packed into that park though than MK.
Your numbers only speak for what the track of the Railroad circles. What about that massive wooded area behind New Fantasyland and the huge parking lot in Tomorrowland that guests will never see? Do you consider that part of the park? Speaking on guest experience, so... including attraction show buildings, Disneyland will be bigger. If you consider areas of the park that guests will never step foot on, then yes the Magic Kingdom railroad circles a larger area.