Railway(s) and there advantages and limitations in ww1?

Answer 1

The Schlieffen Plan was predicated on the use of the German railways to move large numbers of troops very rapidly across Europe. This was the first time that this had been considered. Narrow gauge railways were also used to move troops and munitions about the front. Although I hate quoting wikipedia it does have an article on War Department light railways at:- http://en.wikipedia.org/wiki/War_Department_Light_Railways.
The railways in the UK were used to move large numbers of troops to the channel ports and special ambulance trains met ships returning with injured soldiers.

Answer 2

THEIR advantages were in moving large numbers of men & material overland quickly.

Roads were not paved, or even existing in many areas before and during WW1.

Massive guns could be moved around on rails, guns that horses and cars could not move. But those guns were limited in mobility, so aircraft could often attack them once bombing came in.

Aircraft reaching out beyond the battlefield, once bombing was figured out, railroads were a prime target (more so in WW2). RR took time to build & repair once damaged.