How to create a column with rows in postgres?
You could try adding a json array column (json[]), but it depends on your access patterns  what the best column type would be. 

Example:

ALTER TABLE tableName
ADD COLUMN timeTableRows json[];


And then:

INSERT INTO tableName 
(
    timeTableRows
) 
VALUES
( array['{
   "type": "DEPARTURE",
   "scheduledTime": "2020-01-26T04:57:00.000Z",
   "causes": []
 }',
 '{
   "type": "ARRIVAL",
   "scheduledTime": "2020-01-26T05:02:00.000Z",
   "causes": []
 }']::json[])