I'll be arriving in LHR at 9:35 am and plan to take the HeathrowExpress to Paddington after I clear in customs and baggage. This flight is usually on time from my experience. I'm just always wary of messing up internal travel times. I have 2 hours to get off the plane and get onto my departing train....think it's reasonable or should I take a later train like the 11:55?

Where are you going as going into London may not be your best choice - especially if you are willing to pay for the HEX

Either take the tube (Picaddilly line) or just rock up to the HEX when you get there and get on the next train? No need to fixate on what time you train departs from Paddington.

I have experienced really long lines at H M Customs in Heathrow - step quickly once off the plane to Customs as soon as possible - are you buying a discounted ticket - if so these may not be refundable nor changeable and full fare tickets may literally cost a whole whole lot more - tickets that can be used on any train - if doing these just head to Paddington and take the next train and buy ticket there (ask for any discounts available at the ticket window) - trains are so so frequent - but if doing the www.nationalrail.co.uk deep discount tickets then I'd leave another hour between trains and if in Paddington early just ensonce yourself in one of the station's many restaurants, pubs, etc.

It also makes a difference which Heathrow terminal you are arriving in - Heathrow Express is right in terminal 4 and I assume the new terminal 5 but if landing at terminals 1, 2 or 3 there is a unified Heathrow Express station that is a much longer walk to get to - if i recall correctly.

It also makes a difference which Heathrow terminal you are arriving in - Heathrow Express is right in terminal 4 and I assume the new terminal 5 but if landing at terminals 1, 2 or 3 there is a unified Heathrow Express station that is a much longer walk to get to - if i recall correctly.

Why do you feel you need to buy in advance??? There is a Heathrow Express ticket sales counter AFTER customs as well as you can just pay once onboard.

alanRow's post is important and may be lost in all the rest.

WHERE are you heading? Going in to Paddington may not even be necessary.

For example you can dodge the pricey Heathrow Express if heading to the West Country from Paddington by taking the Rail bus or regular bus to Reading, a stop on the mainline from Paddington to The West. But if going to places like the Midlands then head to Paddington.