The RMT has this morning accused tube bosses of allowing stations to become "dangerously overcrowded" during the second say of strikes.
Members of the Rail, Maritime and Transport union will end a 48-hour walkout at 9pm tonight, with a further, three-day stoppage planned for next week.
LU said half of train services ran yesterday and two-thirds of Tube stations were open, much more than during a previous strike in February.
Nearly 90% of the usual number of Oyster cards were used on Transport for London's network, according to the company.
But there was still huge disruption to travel, long delays for Tubes and big queues for buses.
The fight broke out as the train approached Aldgate East station on Monday night, hours after the Tube strike began.
Fog and train delays added to the misery depriving many travellers of alternative ways to get to work.