I've seen some really weird layouts in my time - a prison in a remote place seems logical in comparison to a railroad that carries batteries from a recharging station to the bottom of a quarry, or a railroad carrying fishfood from the stores, and tips it in the lake at a fish farm!
A prison uses up lots of food, supplies, water, fuel for heating and cooking, and produces lots of waste and rubbish. All that has got to go somewhere, and in a remote place where there is no sewer, no water supply, no rubbish collection, but has a railroad nearby, taking it all by train seems pretty logical to me. :thumb:
Think about it, box cars, oil tanks, coal hoppers, armored prisoner transport cars, and armored locomotives - you'd have plenty going on there.