Broken-down trains and signalling problems have caused morning rush-hour chaos which also affected those travelling to three busy airports for the Easter holidays.
The first incident was at Balham in south London where a broken-down train led to delays to services run by Gatwick Express and the Southern train company.
All routes through Balham were affected, with a number of services to and from London's Victoria station held up.
The second breakdown affected a train between Ely and Waterbeach in Cambridgeshire. Among the services that were delayed were those run by the CrossCountry train company between Birmingham
New Street station and Stansted Airport in Essex.
In northern England, trains run by First TransPennine Express between Manchester Airport and Leeds were among those delayed by a signalling problem near Manchester.
Northern Rail was also affected, with delays between Manchester Piccadilly station and Leeds.
In another incident, a broken-down train between Aberdeen and Dyce led to morning rush-hour delays to ScotRail services between Aberdeen and Inverness.
Another traveller, Christopher Riley, tweeted: "1 hour and 45 mins and still not at victoria. Shamefull."
Initially, travellers were told that the Balham incident was likely to be over by 10am. But another broken-down train - at Clapham Junction - meant that delays were expected until 2pm.
Some Gatwick Express services were cancelled and others were subject to delay. Passengers were told to expect Southern train service delays of up to 50 minutes in and out of Victoria.
Frustrated passenger Piers Henderson tweeted: "Victoria trains stop at E Croydon, people can't fit on trains and Gatwick Express sails through half-empty."
Theresa Roberts tweeted: "Yet again trying to leave London on the gatwick express is a nightmare. Hope we don't miss the plane."