When a train leaves there, it has to go from the height of the station down to the river bed level and then back up to the level of the Lexington Ave & 60th St station. The N/W platform at Queens Plaza is an elevated station. The tunnel runs between the Queens Plaza station and the 60th St/Lexington Ave. The steepest grade for a train that goes under the East River is where the N,R and W go through the 60th st. How high close to or above street level the lines are on either banks will dictate the gradient necessary to make that trip. This is because the part of the tunnel in the middle of the river sits on the river bed for support. Some of the steepest grades in NYC subway are along its tunnels. The grades on all the functional bridges across the East River are about 3.4%. In most cases, grades of 3% (or 1.72º) can be considered normal while there is a good number of cases where it is exceeded. Besides, there are stations with one set of platforms on top of another, such as the 59th St/Columbus Circle, West 4th St., and 7th Avenue (B/D,E). In Brooklyn and Queens, the terrain is richer. While Manhattan is pretty flat, there are a few ups and downs as you go further north. The New York City subway is full of gradients all over its network. In certain cases where a steep gradient is non-negotiable (such as up a hill), power is supplemented using additional locomotives - often with a second engine upfront, or one at the rear of the train pushing it.Įlevation profile of the Lexington Ave (4/5/6) line (Source: ) When constructing gradients for train lines, there is a strict lower limit depending on the amount of space available (you cannot justify a 3mi ascent to a 0.5mi bridge) and an upper limit depending on the maximum tractive power of the locomotive running over it. On gradients, however, lack of friction is a massive hurdle to get over. On flat surfaces, this works out in its favor as there is very little friction to resist movement, and results in an energy efficiency so high that it makes trains one of the most sustainable modes of transportation. Steel on steel, once things get rolling, results in incredibly low friction. This is because one of the greatest advantages of a train system is also its bane: the lack of friction. Free-body diagram of a train going up a slope (Source: )

Nyc subway system