Since the train stops only for two minutes at the boarding point, it will be difficult fo you to book it in the luggage van. If you are not getting the Station number to respond, please get in touch with any porter/luggage attender who can answer whether it can be loaded or not. Normally, I would think NOT. But things have changed since the Luggage/Brake van in the front of the train have been contracted out to private parties. Therefore my suggestion.
Please share your experience after the journey. Good wishes.