you have to go to old delhi railway station, from sarai rohilla there is no loading as far as i know. and it would be better to book it till najibabad, if you are going in the same train. as when i booked for my bike from kotdwar to delhi they told me that if i book from kotdwar my bike would reach day after tomorrow, and they suggested me to book from najibabad as i was travelling in the same train. regarding packing you will get person there in the delhi railway station itself.