Crowe was released by Luton Town last season, and finsihed the campaign with Oldham Athletic.
He has scored 32 times in 154 appearances through his career.
Sheffield United youngster Billy Sharp is the other trialist, who is at Glanford Park with a view to a season-long loan.
He netted 18 times for the Blades' youth team last season, and also scored seven times for their reserve side.
Iron manager Brian Laws will also be keeping a close eye on the visiting Rangers players tonight, with one of them likely to be on his way to North Lincolnshire as this season's `Loan Ranger`.