It was soon found that the viaduct approaching London Bridge would be inadequate to deal with the traffic generated by four railways, so it was widened by the Greenwich Railway between 1840 and 1842, doubling the number of tracks to four.
Ret hurtigt stod det klart at indkørslen ind til London Bridge ikke var tilstrækkelig til fire selskabers trafik, så mellem 1840 og 1842 udvidede Greenwichbanen den, med en fordobling af antallet af spor til fire.