A £10,000 reward was offered today after two vandal attacks caused damage to three trains, including one travelling at more than 100mph.
The incidents, in which trains struck debris deliberately placed on the tracks in Tamworth, Staffordshire, could have had catastrophic consequences, British Transport Police (BTP) said.
Network Rail and train operator CrossCountry are offering the £10,000 reward to anyone who provides information which leads to the arrest and conviction of the offenders.
No-one was hurt after objects, including concrete blocks, tyres, wooden pallets and sandbags, were placed on the tracks near Wilnecote station last Thursday and Friday.
Detective Chief Inspector John Sidebottom, of BTP, said: "It is imperative that we trace those responsible for causing these incidents.
"Thankfully no-one was seriously injured in either incident, but the reality is that we could have been left dealing with mass casualties or even, in a worst-case scenario, fatalities."
The first incident happened at around 11.30pm on Thursday, when a Nottingham-to-Birmingham passenger service struck debris, forcing the train to be taken out of service.
Two other trains, one travelling at more than 100mph, also hit debris on the same stretch of line shortly before 6am on Saturday, leaving one driver suffering from shock.
Chris Rowley, Network Rail's area general manager, said: "This sort of senseless vandalism puts the lives and safety of innocent people at risk.
"It also causes a huge amount of disruption for passengers, as well as thousands of pounds of damage.
"We are committed to tackling trespass and vandalism on the railway and hope by offering this reward we will not only catch those involved, but enable passengers and train crews to continue using the railway safely."
In a bid to prevent further acts of vandalism, BTP has stepped up patrols in the area and is asking members of the public who live or work nearby to report anything suspicious.
Mr Sidebottom said: "I cannot over-emphasise the danger posed by this type of crime and urge anyone with information to come forward.
"Thankfully, so far, no-one has been seriously injured, but we may not be so fortunate if this happens again."
Anyone with information about the incidents at Wilnecote is urged to contact BTP on 0800 40 50 40 or the Crimestoppers hotline on 0800 555 111.Reuse content