Travelling from Shanghai to Beijing

We are travelling from London, UK and are exhibiting at a Trade Show in Shanghai in early September. After the show ends, we will be travelling on to Beijing for a few days of tourism. Our flights are arranged as arriving from UK into Shanghai and departing to UK from Beijing.

We wish to travel to Beijing from Shanghai by rail and would like to use the high speed "G" trains. We will have our trade show equipment with us as well as our personal luggage. Your website (which has been very helpful) suggests that baggage which is over the personal allowance of 20kg needs to be placed in a luggage carriage but that G trains don't have them.

Our extra luggage is not heavy, but is bulky as it will be a trade show exhibition stand. What would you suggest we do? How easy is it to arrange for our excess luggage to be placed on a luggage coach? Can we do this using your service? Should we abandon the railway idea and simply fly between the two cities although we would imagine the baggage allowance is also prohibitively expensive?

Many thanks for your help,
Joanne