When the leaves begin to fall, those that land on the damp surface of the rails are crushed under thousands of tons of steel.
For those passengers who aren’t familiar with leaf oil season, when the leaves begin to fall, those that land on the damp surface of the rails are crushed under thousands of tons of steel. An oily, gelatinous chemical compound called pectin, which is the chief component of the cell walls in these leaves, coat the surface of the rails and eliminate the frictional forces between the steel train wheels and the steel railhead, resulting in slow, slippery climbs up hills and difficulties pulling into and out of station stops.
While we try to compensate for the slippage by adding an additional locomotive to our trains, leaf oil season (all of autumn) can often result in train delays.
More information can be found at: https://en.wikipedia.org/wiki/Slippery_rail