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I see two basic issues with the example posted in the question:

1. The <param> tag in the launch file set's the parameter name to param_1. So we will have a parameter /trial/param_1 with a value determined by the station arg to the launch file. However, the node tries to read a parameter called /trial/param_from_launch.
2. You have not set the output attribute for the node. So even if your node did work as intended you wouldn't see the output messages you're hoping to see (except the calls to ROS_ERROR).

What if you change your launch file to:

<launch>

<arg name="station" />

<node pkg="roscpp_tutorials" type="trial" name="trial" output="screen">
  <param name="param_from_launch" value="$(arg station)" type="int" />
</node>

</launch>