The sensor value is the number of minutes to the next departure (or if something else is configured that will be used instead). There are also a large number of attributes that can help you with filtering or whatever you need:
friendly_name: Mölnvik
unit_of_measurement: min
icon: mdi:subway
attribution: Stockholms Lokaltrafik
last_refresh: 2018-11-16 19:08:40
next_departure_minutes: 10
next_departure_time: 19:18:40
deviation_count: 1
refresh_enabled: on
departures: [{
line: 474
direction: 1
departure: 10 min
destination: Slussen
diff: 10
type: Buses
groupofline: blåbuss
icon: mdi:bus
}]
deviances: [{
updated: 2018-11-16T15:59:40.063+01:00
title: Inställd avgång
fromDate: 2018-11-16T15:59:40.663
toDate: 2018-11-17T00:00:00
details: "Mölnvik kl 16:17 till Slussen är inställd pga framkomlighetsproblem - köer."
sortOrder: 1
}]