“At a sprawling campus north of New York City, a 3-year-old German Shepherd named Johnny frantically sniffed through seats and luggage bins on an out-of-service commuter rail train trying to catch a whiff of hidden explosive. When Johnny found a black bag with the faint scent of C-4, commonly used to blow up buildings, he sat statue-still at attention, alerting handler Kevin Pimpinelli of the Metropolitan Transportation Authority police to his discovery. In return, Pimpinelli rewarded him with a prized chew toy. Johnny is one of 50 of the transit authority's police dogs being trained at its $13 million, 72-acre training centre in Stormville, New York, about 70 miles (113 km) north of New York City. The Metropolitan Transit Authority operates subways, buses, and railroads in New York, New Jersey and Connecticut and provides more than 2.7 billion trips each year to travellers, according to the agency's website.

The canine training centre, the biggest facility of its kind in the United States, begins full operations and will train dogs used by police across the nation. Amid attacks including the March bombing of a Brussels train station and airport, which killed 32 people, U.S. police agencies see highly trained dogs as key to maintaining security in large public spaces. Their sharp sense of smell exceeds the ability of humans and machines to detect explosives and track suspects. The dogs are carefully selected. Only about one in 30 dogs assessed at breeders are chosen for the canine police force. The dogs are mainly German Shepherds like Johnny or Belgian Malinois, high-energy breeds known for a strong desire to work. The MTA dog training facility includes rooms modelled after classrooms and bus stations, 26 kennels and a veterinary clinic. Outside, there are nine buses, ponds and train cars at the end of a retired Metro North railroad track. All are used to train the dogs. While there is no central database tracking the number of police dogs in service in the United States, the USPCA estimates the figure at about 10,000. Typically they work until about the age of 10, after which they normally go on to live as pets in their primary handlers' homes”. – Mike Segar and Laila Kearney via Reuters



Metropolitan Transit Authority (MTA) Police Officer Keith Flood trains with his K-9 partner Doc, a German Shepherd, inside the “warehouse room” at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police Officer Nelson Hernandez interacts with his K-9 partner Geo, a long haired German Shepherd, in the kennel area of the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police Officer Keith Flood trains with his K-9 partner Doc, a German Shepherd, inside the “warehouse room” at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police Officer Jason Wharton watches as his K-9 partner in training Mikey, a German Shepherd, indicates he has found an explosive by sitting, inside a training room in the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police Officer Kevin Pimpinelli works with his K-9 partner Johnny, a German Shepherd, during a simulated bomb search aboard a dedicated Metro-North Railroad commuter train car permanently installed for training at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police Officer Kevin Pimpinelli works with his K-9 partner Johnny, a German Shepherd, during a simulated bomb search aboard a dedicated Metro-North Railroad commuter train car permanently installed for training at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Lucky, a Metropolitan Transit Authority (MTA) Police dog in training, stands between officers as they train inside the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police Officer Daniel McCade and his K-9 partner Droga, a Belgian Malinois, work during a simulated bomb search near dedicated MTA busses permanently installed for training at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police Officer Kevin Pimpinelli works with his K-9 partner Johnny, a German Shepherd, during a simulated bomb search outside a dedicated Metro-North Railroad commuter train car permanently installed for training at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





A Metropolitan Transit Authority (MTA) Police K-9 explosive detection dog leaps over an obstacle during agility training at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police Officer Jason Wharton interacts with his K-9 partner Mikey, a German Shepherd, as they train at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police Officer Jason Wharton walks with his K-9 partner Mikey, a German Shepherd, as they train outside the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police K-9 explosive detection dogs sit on command during agility training at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police K-9 explosive detection teams train on the agility course at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)





Metropolitan Transit Authority (MTA) Police K-9 explosive detection teams train on the agility course at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)