Network Rail is appealing against a ruling that it has to compensate a homeowner whose bungalow is dominated by knotweed on a railway line.
Robin Waistell won his case in February following a four-year legal fight over his property in Maesteg, south Wales.
It was seen as a possible test case for homeowners whose property is blighted by knotweed on railway embankments.
A lawyer for Mr Waistell said they hoped to have the case transferred to the Court of Appeal by early 2018.
Mr Waistell said the case could have been avoided if Network Rail had dealt with the knotweed five years ago, when he contacted them about the problem after he discovered he could not sell his house for its potential value because of knotweed growing on adjacent land.
He had asked for £60,000 in compensation for loss of value on his home, but was awarded £15,000 in February, with part of that to pay for an insurance-backed guarantee on a herbicide programme to tackle the knotweed.
His lawyer Rodger Burnett told BBC Radio Four's You and Yours programme: "If [Network Rail] are found to be liable they could be facing a very substantial bill [from similar cases]."
Network Rail declined to speak to the programme.