Tens of thousands of mainline South West Trains (SWT)commuters into Waterloo suffered an horrendous start to the week as two separate lots of over-running engineering work and a signal failure caused major delays.
Some trains were cancelled and replaced by buses and others diverted.
Trains were halted on the main Portsmouth route into London between Guildford and Woking; some services were diverted via Cobham & Stoke D'Abernon. There was a bus replacement service between Guildford and Woking.
The line reopened around 7 am but knock-on delays continued.
Disruption followed a late finish to Network Rail engineering work on a bridge.
At the same time there was also a late finish to engineering work on the busy commuter route between Strawberry Hill and Barnes via Twickenham. This was completed by 6.30 am but again resulted in knock-on delays.
The third problem - a power failure followed by a signal breakdown - disrupted long-distance services from Exeter St Davids via Salisbury and Woking into Waterloo.
A Network Rail spokesman said: "We really do apologise for the problems suffered by passengers this morning.
"There was a programme of major engineering work between Guildford and Woking on a bridge and we were late finishing. We restored a normal service as quickly as we could but this did result in some knock-on delays.
"A full service was restored between Barnes and Strawberry Hill shortly after 6 am but again there were knock-on delays.
"We are still investigating the cause of the signal problem on the main route between London and the West of England. There was an earlier power failure and a later signal problem."
First Capital Connect (FCC) services from Bedford into London Blackfriars suffered 20 minute delays at the height of the morning peak due to a broken down train near Bedford.
A signalling problem caused delays of up to 30 minutes for Greater Anglia trains from Walton-on-the-Naze via Colchester into Liverpool Street,
On the Tube there were minor delays to District line services between Dagenham East and Upminster due to signal failure at Dagenham East.
