Train spotters are being warned to keep off the tracks as the Doncaster-built Flying Scotsman begins a tour of England and Wales.
The train's inaugural run following a decade-long refit was marred by trespassers earlier this year, with Network Rail forced to pay out almost £60,000 in compensation when 59 train services were delayed by people encroaching on the track to get as close as possible to the famous locomotive as it travelled from London to York on February 2.
All trains on the East Coast Main Line were temporarily stopped, causing a combined total of more than eight hours of delays.
Network Rail's managing director Phil Hufton called on enthusiasts making plans to see Flying Scotsman as it visits various parts of England and Scotland over the next few months to stay safe.
"While the turnout to see Flying Scotsman so far has shown the passion and support for steam engines, and indeed the railway itself, the images of people stood on the railway taking photographs were deeply concerning and a breach of our safe operations," he said.
"I cannot stress enough how dangerous it is to go onto the railway without any formal training and without permission, as well as being illegal.
"I am urging those who plan to enjoy seeing Flying Scotsman in the coming days to do so from a safe position and do not go onto the railway under any circumstances."
The National Railway Museum in York bought the locomotive for £2.3 million in 2004 before work got under way on its restoration in 2006.
It is not publishing the timings of its tour in a bid to reduce the chance of people disrupting mainline services.
Jim Lowe, head of operations at the museum, said: "It is vital that spectators do not venture onto the railway, particularly when it is on the mainline as a full timetable of regular services will be running.
"In order to avoid overcrowding and incidents of trespass neither ourselves nor our partners will be publishing recommended viewing points or the timetable of when the train will be passing through specific locations."
The decision has angered a number of members of the public keen to catch a glimpse of Flying Scotsman.
Andrew Burnie posted on the NRM's Facebook page: "Really sad that the timings for these runs seem to have been hidden.
"Was looking forwards to seeing the Scotsman in Edinburgh this weekend but because of the idiots who took to the tracks I now can't find the times it will be departing from and arriving to Waverley as they have been taken down to avoid a repeat.
"The daft minority spoiling things once again."
Built in Doncaster in 1923, the Flying Scotsman soon became the star locomotive of the British railway system, pulling the first train to break the 100mph barrier in 1934.