Railway reserves the right to procure the material only from Proven Sources having satisfactory past performance of supplying the tendered items to Railways. The tenderers must upload documents pertaining to their credential / past performance in Zonal Railway/PUS/Other Govt. Organization, i.e. copy of purchase order corresponding challan, inspection certificate & R/Note in support of the same to be uploaded. If firm failed to upload/attach the said documents then their offer will not be considered as a valid offer and summarily be ignored. No back reference on either side will be made or entertained in this regard.