Near Liverpool Street Station

Not sure what this is called its at the back of Liverpool Street Station when there at lunchtime. Eeks I was sooooooooo late for work today a passenger took ill so someone pulled the emergency cord before we got to Hither Green so we stopped mid station - eventually we chugged into the station, the train was terminated and we picked up another one but OMG got to London Bridge almost 30 mins late :)