Calm is a different concept from Trouble. Trouble is a synonym of Anxiety. 
Excessive is related to Burn. Burn is a synonym of Burning. Gas can be used for Burning. Gas is related to Station. 
Calm <--DistinctFrom--> Trouble <--Synonym--> Anxiety 
Excessive <--RelatedTo--> Burn <--Synonym--> Burning <--UsedFor-- Gas <--RelatedTo--> Station 