Goals from Lee Cook and Shabazz Baidoo put QPR on top and cancelled out Eddie Johnson's opener, but Luke Varney and Billy Jones restored Crewe's lead.
In the second half Simon Royce did well to stop Steve Jones extending Crewe's lead and this proved vital.
On 57 minutes Rowlands' long-range effort drew QPR level before Langley hit the winner with nine minutes left.
QPR boss Ian Holloway:
"We already have more points than we did at this exact point this time last year with a game hand.
"But that doesn't seem to be good enough for some people. I'm sick and tired of every Tom, Dick and Harry getting linked with my job every day.
"Well ding, dang, doo. It's my job, I own it and it's up to anyone else to take it off me."
Crewe: Turnbull, Tonkin (Rodgers 69), McCready, Foster, Moss, Vaughan, Billy Jones, Lunt, Gary Roberts, Johnson (Varney 37), Steve Jones.
Subs Not Used: Tomlinson, Rix, Walker.
Booked: Billy Jones.
Goals: Johnson 15, Varney 39, Billy Jones 45.
QPR: Royce, Rose, Santos (Milanese 69), Shittu, Bignot, Cook, Rowlands, Bircham (Ainsworth 21), Langley, Nygaard (Furlong 69), Baidoo.
Subs Not Used: Moore, Donnelly.
Goals: Cook 35, Baidoo 37, Rowlands 57, Langley 81.
Ref: K Wright (Cambridgeshire).