Police surrounded Harrow and Wealdstone Station in an attempt to capture a suspected burglar.
Dozens of officers were called to Princes Drive yesterday (Wednesday) to reports of a teenager trying to break into a house.
Police were originally alerted at 3.34pm, but lost sight of the suspect after a brief chase.
He was then spotted by a member of the public coming onto Ellen Webb Drive from the railway track at 3.50pm before police lost him again until 4.02pm, when he was sighted near the bridge over Hailsham Drive.
The suspected burglar led police, dogs and a helicopter on a half-hour chase.
The youth fled onto the railway tracks before eventually being caught in a nearby garage.

Police arrested a 15-year-old boy in connection with the incident.