The city follows a largely grid-style urban layout, with the roads follow a slightly tilted northwest-to-southeast orientation due to the South Manchurian Railway, which runs perpendicular to that direction. The streets in Shenyang are almost always named according to a routine convention — one that runs more in the north–south direction is called a "street" (街; Jīe) or "avenue" (大街; Dà Jīe; 'big street'), and one that runs more east–west are call a "road" (路; Lù) or "boulevard" (大道; Dà Dào; 'big path'). The only exceptions to this rule are the east–west Middle Street in Shenhe District, which takes its historical name from ancient times (though its modern official name is actually the "Middle Street Road"); and the north–south Minzhu Road (民主路) in Heping District that traverses diagonally across the superblock between the Shenyang Railway Station and the Zhongshan Park, but as one of the only three diagonal streets in the entire city it is accommodated as a "road" instead of "street" in keeping with the other two diagonal counterparts that run east–west.