To find the average speed of the train, you can use the formula for average speed:
\[ \text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}} \]
In this case, the total distance is 120 miles and the total time is 2 hours.
\[ \text{Average Speed} = \frac{120 \text{ miles}}{2 \text{ hours}} = 60 \text{ mph} \]
So, the average speed of the train is 60 mph.