Substantial is a synonym of Massive. Massive is a synonym of Significant. Significant is a synonym of Relevant. 
Column is related to Pole. Pole is related to Location. West is a type of Location. 
Substantial <--Synonym--> Massive <--Synonym--> Significant <--Synonym--> Relevant 
Column <--RelatedTo--> Pole <--RelatedTo--> Location <--IsA-- West 