pub fn update_vel_indicator(
velocity_indicator: Single<'_, '_, (&Target, &mut TextSpan), With<TrainVelocityIndicator>>,
q_trains: Query<'_, '_, Ref<'_, Velocity>, With<Train>>,
)pub fn update_vel_indicator(
velocity_indicator: Single<'_, '_, (&Target, &mut TextSpan), With<TrainVelocityIndicator>>,
q_trains: Query<'_, '_, Ref<'_, Velocity>, With<Train>>,
)