A smashed train window following the attack on the train in Bradford
Vandals who have caused a significant amount of damage to two Bradford trains are being hunted by transport police.
On two separate occasions missiles have been thrown at trains in West Bowling.
The windscreens were broken on two consecutive days.
It happened on Sunday 25 and Monday 26 July.
The first incident took place when a large object was thrown at the 5.12pm Leeds to Halifax service train from a footbridge just off Dalcross Grove.
The second happened at 9.10pm the next day, when an object was thrown at the 8.37pm Leeds to Manchester Victoria service, shattering the windscreen and showering the driver with shards of glass.
Inspector Cameron Young is from British Transport Police (BTP) . He says it's a miracle these acts of vandalisms did not cause serious accidents.
British Transport Police are on the hunt for the vandals in the Bradford area
He explains: "Objects were thrown from the railway bridge at trains and on both occasions they have stopped the trains and damaged the windscreens.
"Luckily no-one was hurt but it could have had very serious consequences.
"But it could have been a complete disaster."
Police are appealing for information and Northern Rail is offering a reward of up to £1,000 for information leading to the arrest, charge and conviction of the vandals responsible.
Detective Sergeant Matt Davies is the investigating officer.
He says: "The object struck the train, smashing the inner and outer skin of the windscreen. The train was taken out of service as a result, and trains were placed on caution, causing delays to passengers."
Four youths were seen running away from the area following each incident and detectives are appealing for anyone with information about the incident or those responsible to come forward.
DS Davies adds: "Throwing objects at fast moving trains is an extremely foolish and dangerous offence and we will arrest anyone found committing such an act.
"I am appealing to any members of the public who were on the train or in the area at the time who may have witnessed the incident to come forward and contact us."
Steve Butcher, Chief Operating Officer for Northern Rail said: "We will not tolerate any act of vandalism that threatens the safety of our employees or passengers.
"That is why we are offering the reward for information leading to the successful arrest and conviction these offenders.
"I would urge anyone with information to contact the British Transport Police before these people act again with potentially more serious consequences."
Anyone with information is asked to contact British Transport Police on 0800 40 50 40 quoting incident number B9 NEA of 03/08/2010 or call Crimestoppers, anonymously, on 0800 555 111.