Answer:
a = 2.77 [m/s²]
Step-by-step explanation:
To solve this problem we must use the following equation of kinematics.

where:
Vf = final velocity = 19 [m/s]
Vo = initial velocity = 44 [m/s]
a = acceleration [m/s²]
t = time = 9 [s]
Note: The negative sign in the above equation means that the train is decreasing its velocity.
19 = 44 - a*9
9*a = 44 -19
a = 2.77 [m/s²]