I'm not sure what you mean by a "safety shut down," but the TC40D doesn't have any sort of "Master Reset." To start, though, make sure you're in N, have the brakes applied, and don't have either PTO activated.
You might want to check under the tractor for any loose wires, though. I once shut down my TC40D, and couldn't get the thing to restart, no matter what. When I looked underneath, I saw a wire connector had been pulled loose, and upon figuring out where to plug it back in, the tractor started right up. If you're doing everything normally, and the tractor won't turn over, I'd start looking for some dangling wires.
- Jay