Update: This story has been edited to reflect new information on the Crossrail’s opening dates.Several years overdue, the highly anticipated Crossrail train service from central London to Heathrow Airport (LHR) has been further delayed.Software and system issues forced the delay, which will allow more time for testing.Some new trains will begin running between Heathrow and Paddington Stations in March of next year, but the full “Elizabeth” line is not expected to begin operations until at least 2021.The new Crossrail service from Paddington to Heathrow will average about 24 minutes.Heathrow Express will remain the faster option, clocking in around 15 minutes, though it is more expensive.Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.Once operating, the new Elizabeth line will see six 1,500-person capacity trains per hour run from popular London locations like Bond Street, Liverpool Street and Canary Wharf through to Heathrow Airport, significantly quicker than existing Tube services.Four of the six trains per hour will operate to Terminals 2/3 and 4, with the other two operating to Terminals 2/3 and 5. Crossrail journeys from Heathrow Airport to Zone 1 (or vice versa) will cost £12.10 ($15.5) each way, which is more than twice the cost of the existing — though much slower — Piccadilly line, the Evening Standard reported. The convenient but expensive Heathrow Express will continue to operate, though it has been reducing its ticket prices in anticipation of the increased competition.An information board for the new Elizabeth Line at Tottenham Court Road station in London (Photo by Victoria Jones/PA Images via Getty Images)Related reading: How to save on your next Heathrow Express journeyCrossrail will also eventually help reduce the burden on London Underground’s busiest line, the Central line, as both lines share five stops.The overall cost of the Crossrail project has also now ballooned again by more than $790 million dollars to more than $23.1 billion, with final sections not scheduled to operate until at least 2021.