Trying to put this all in some sort of time order:
INCIDENT 2: 1B53
Local BBC News reports
1B53 passengers had an 8 hour journey to London. From RTT, it looks like this train called at Leicester but then diverted to Corby. Whether it then somehow came back through Leicester (picking up the 180 mins delay time), I don't know - this conflicts with the official report below.
INCIDENT 3: THE CORBY AREA
Official report from Network Rail
16:01: Driver of 1D43 reports bank slip and water above rail head near Corby line. Driver is currently checking track.
16:15: 1D43 trapped as rear bogie completely cover in silt.
16:29: Driver of
1C52 reports water is freely running and covering the down (towards Leicester) line. Water is rising on the (towards London) line and covering the rail in certain areas but passable at 5mph.
16:40: (towards London) line to be cleared at extreme caution by
1C52/
1C55. 1B53 (the last in the queue) will be used to evacuate 1D43.
16:45: 1C52 now reports that the track beyond 1D43 is completely under water and they are unable to pass. Both lines now at a compete job stop.
16:491C52 to be used to evacuate passengers, 1C55 and 1B53 will return wrong direction and cross over at Manton Junction.
EDIT: Perhaps this is where 1B53 picked up the ~180 min delay.
16:50: Network Rail staff arrived on site. Three trains (1C52, 1C55, 1B53) stood on (towards London) line. One train (1D43) stood on (towards Leicester) line.
BBC News link: Flood passengers stranded on rescue train
REPORT FROM PERSON ON 1B53 A TRAIN (BBC News):
After rescuing passengers from 1D43, the rescue train headed south towards Corby.
The train stopped and sat in tunnel near Corby for an hour as the landslip / flooding had got worse.
It then turned back around to head towards Leicester.
However due to further flooding, it stopped before getting very far.
It was then decided to evacuate using the power car door where passengers had to head past a scrap yard (clue to exact location?) and on to buses.
The news report on the radio suggests the person was "on the 15:00 from Leicester". The news reporter says 15:10 from Leicester, which would make the train 1B53.