The circular quoted by Mr. Ram Avtar Singh is very old one.
After that, the whole Cenvat Credit Rules were amended and the new rules state as under:
The Input Cenvat can be booked only on receipt of goods in the factory. If goods are not received in factory then, the purchaser cann't book CENVAT in his books. Accordingly, Co.Y cann't book CENVAT in its books.
Secondly, Since goods are transported by Co.X directly to Co. Z on consignment made by Co. Y, Co. Y shall issue its invoice on which it shall mention the original manufacturer & the excise duty paid/payable to him and then forward this Excise Invoice to Co. Y which shall allow Co. Y to take credit.
The case would have been similar had, Co. Y received the goods in the factory & then removed them to Co.Y. But in that case, Co.Y could book the CENVAT in its books and at the time of removal it will have to pay duty equivalent to the CENVAT Booked under Rule 8 of CER' 2002.
For more clarity Refer Rule 4 & 5 of CCR' 2004 & Explanation to Rule 8 of CER' 2002.