According to the station clocks, two babies are born at the exact...

Let the ground frame be $S$ and the train frame be $S'$.

Let Kanpur be at the origin $x = 0$ and Agra be at $x = L$, where $L > 0$.

The train moves from Kanpur to Agra with velocity $v$ in the positive $x$-direction.

The birth of the Kanpur baby is event $K$ with coordinates $(t_K, x_K) = (0, 0)$.

The birth of the Agra baby is event $A$ with coordinates $(t_A, x_A) = (0, L)$.

Using the Lorentz transformation for time, t' = \gamma \left( t -\dfrac{vx}{c^2} \right).

The time of birth of the Kanpur baby in the train frame is t'_K = \gamma \left( 0 -\dfrac{v(0)}{c^2} \right) =$0$.

The time of birth of the Agra baby in the train frame is t'_A = \gamma \left( 0 -\dfrac{vL}{c^2} \right) = -\dfrac{\gamma vL}{c^2}.

Since $t'_A < t'_K$, the Agra baby is born earlier in the train frame.

Therefore, the Agra baby is elder in the reference frame of the train.