As long as all the trains run near enough to time then it works fine, the problem is if a train is delayed then it will delay the one behind it while it clears the (very long) section which in turn will delay the one behind it etc etc. There isnt much margin for error and it could take a while to recover the service.
Some info forwarded to me-
On the down only one signal is bagged which is DM206 on the end of Dawlish platform so the section is basically from Langstone Rock to just after the tunnels.
But on the up there are 3 bagged UM207 (before Parsons tunnel) , UM208 (in between a couple of the tunnels) and E17 (just after Dawlish platform) so the section is from just after Teignmouth station all the way to just after Langstone Rock.
A couple of signals have had their aspects restricted to conform with the (nearly) normal signalling rules as well, on the down E72 is red green only, (then the bagged DM206), DM207 has no red aspect so is a distant for DM208 which is normal.
On the UP, UM208 is red/green only (then the 3 bagged ones), then E19 has no red aspect and is a distant for E21 (just before Dawlish Warren) which is normal.