Most home insurance policies can have "high risk" (all-risks) added to them
This allows you take any and all possessions, up to the value limit, out of the premises and for any purpose
This includes mobile phones, PDA, laptops, and model railways!
Some insurers prefer you to list specific items, but these policies tend to be expensive and over-priced, so check for insurers with general policies, the additional cost is about 5% to 8% of a policy without all-risks
However, you should note that the policy does NOT include these items once they are in an UNLOCKED vehicle (check the small print)
This will allow you to transport your model railway, from home in your own vehicle or a hire vehicle, to/from an exhibition and/or club and/or meeting
However, it does NOT include its use once there
You would then need public liability insurance, but most clubs or exhibtions should have their own and you are normally asked to contribute to this