Thameslink operates a train from St Albans to Chelmsford every 15 minutes. Tickets cost $12 - $17 and the journey takes 27 min. 2 other operators also service this route. Alternatively, Green Line (operated by Arriva) operates a bus from St Albans to Chelmsford every 30 minutes. Tickets cost $11 and the journey takes 1 h 27 min. Arriva UK also services this route hourly.
From St Albans City train to Farringdon Underground Station, Tube to London Liverpool Street, then train to Chelmsford. 1 h 13 min £25. From St Albans City Railway Station bus to Harlow Town Centre, Bus Station (Harlow Bus Stn) then line 59 bus to Chelmsford City Centre, Railway Station (Chelm Rail Stn). 2 h 40 min £12. From St Albans taxi to Chelmsford. 45 min £183. From St Albans drive to Chelmsford. 45 min £8.