The UK Labour leader tweeted his support for a petition by the Transport Salaried Staffs’ Association (TSSA) urging SNP ministers to ditch the Railway Policing Bill.
The legislation, which will see British Transport Police (BTP) in Scotland subsumed into Police Scotland, will be voted on at Holyrood later today.
It passed its first hurdle at the Scottish Parliament last month despite calls from Labour and the Tories for the move to be reconsidered.
Posting a link to the petition on Twitter, Mr Corbyn said: “In the wake of recent terror attacks now’s the time to strengthen not weaken our Transport Police.”
TSSA general secretary Manuel Cortes said: “Jeremy is showing he is the only party leader that gets the importance of proper policing.
“BTP is a specialist service because the railways have specialist policing needs. They are a highly-vulnerable terrorist target and Jeremy is right, we now need more specialist transport police, not less.”