英國underground

You can use Oyster card from Heathrow Terminal 4 to Lewisham, there is no need to buy ticket from railway station. It costs £4 for a single cash ticket, £3.50 by Oyster card. You only need to pay £3 for a Oyster card deposit. You can return the card and have your deposit back when you finish.

There is an underground station at Terminal 4, for further information, please check,

http://journeyplanner.tfl.gov.uk/user/XSLT_TRIP_REQUEST2?language=en&sessionID=JP08_331870505&requestID=1&tripSelector4=1&itdLPxx_view=detail&tripSelection=on&command=nop

Price details,

http://www.tfl.gov.uk/tfl/tickets/faresandtickets/2007/farefinder/default.asp?from=Heathrow+Terminal+4&to=lewisham&type=Adult&showfares=Show+fares

Hope it helps

你係Heathrow T4落左機出到接機大堂,你就睇返指示牌... 佢會寫住Underground... 你落到去地鐵站就去Ticket Office買張Oyster卡(佢個Ticket Office開到22:30)... Oyster卡就要GBP13 (GBP10 Credit, GBP3 Deposite), 個Deposite退返張Oyster卡比你... 由Heathrow T4去到Lewisham係要GBP4 (普通飛)或者GBP3.5 (Oyster卡)...
之後你上地鐵Piccadilly Line去到Hammersmith對面月台轉District Line去Tower Hill... 去到Tower Hill就去Tower Hill Gateway轉DLR (Lewisham係其中一個總站,如果無直車就坐一個站到Shadwell轉Lewisham車...)...
呢個網 http://journeyplanner.tfl.gov.uk/im/SI-T.html 可以比你check到每一個站Ticket Office開放時間...
而呢個就係倫敦地鐵圖 http://www.tfl.gov.uk/assets/images/general/mapt-tube-standard-colourmap.gif
最後就呢個網 http://ticketlocator.tfl.gov.uk/Oyster_ticket_stop.asp 佢有曬所有Travelcard分類