TC reported "B" side cab door requires much force to open and close. ~~~~~ 3547 TC reported "B" side cab door requires much force to open and close.  3547 B/S cab door roller checked - OK. Checked for any FOD - OK. Checked/found top guide rail loose. Readjusted & retightened door guide rail. Performed cab door open/close cyclic test 10x - OK.  Aminur/Azmi 44422