Earlier, BRC WAP4E was regular for 12968/67 Jaipur-Chennai SF Express. Back then, WCAMs were ruling Vadodara-Mumbai stretch. However, the link was changed to ED WAP4 probably 4-5 years back after WR came under AC traction fully. BRC didn't have WAP5 locos back then.
Still BRC WAP4E hauled JP MAS on some occasions as offlinks.
Now, BRC homes a good number of WAP5 locos too. So, JP MAS Express gets the upgraded link straight away! :D :P
AFAIK this is the third or fourth time JP MAS Exp got WAP5. For the very first time, it got GZB WAP5 and thereafter, BRC :)