Nature's Sculpture. The Subway is one of the best routes in the Park, and hiking up from the bottom gets to the best stuff without ropes and swimming. If you're carrying lots of camera gear, hiking in winter, or you are averse to ropes and swims, it is a great way to see The Subway.
The short version: hike down a 400-foot (120m) steep, loose gully. Pick your way up a rugged streambed for two hours. Enjoy some really nice scenery. Hike back down the streambed for two hours, then up the 400-foot steep, loose gully. If it is at all hot out, hiking in the streambed is hot, hot, hot. Bad hot, not good hot. Save energy for the strenuous hike uphill to get back to the car, and get an early start.
"The Subway" is a short, spectacular section of the Left Fork of North Creek. The canyon is called Great West Canyon. The Subway section is not marked on most maps, but is where the Left Fork tightens up and twists sharply, between North Guardian Angel and Guardian Angel Pass. The hike is also known as "The Left Fork".
Due to its popularity, the Subway is managed under a quota system. Reservations are distributed by lottery several months in advance and are highly recommended. The same permit is used for the Top Down or Bottom Up Subway, so you do not have to decide which way to do in advance. Lottery and Reservations are made on-line at the Wilderness Reservation System.
Be flexible and plan ahead to avoid being denied. A permit is required for hiking The Subway from the bottom or from the top – and it is the same permit. Group size limit is 12.