Coming in hot, coming out cold?

Classical Mechanics Level 2

Grain is loaded onto a train initially coasting at the speed $v_0 \text{ m/s}$ by dropping it vertically from a stationary silo at the rate $\alpha_m \text{ kg/s}$ . How fast is the train moving when it exits from under the silo (in m/s)?

Details

The train is $l = 200$ m long, and has an empty weight of $m_0 = 500$ kg.
$v_0=45$ m/s
$\alpha_m = 20$ kg/s