Answer
0.12 mi
Work Step by Step
$2^{\circ}30'=2.5^{\circ}$
In radians, central angle $\theta=2.5^{\circ}\times\frac{\pi\,rad}{180^{\circ}}=0.04363323\,rad$
Considering the distance 2.7 mi as the radius($r$) and the length of the train as arc length($s$), we can find the length of the train using the relation $s=r\theta$.
$s=2.7\,mi\times0.04363323\approx0.12\,mi$ (rounded off to 2 significant figures)
