I braved the snow to travel on the first northbound Thameslink train
to use the Canal Tunnels, the Horsham to Peterborough. I travelled
from East Croydon to Finsbury Park.

However, I almost missed it at East Croydon: it was increasingly
running late, and there was a last minute, unannounced platform
change, from 4 to 2. Luckily, I spotted the changed departures board,
and just made it up and down the ramps in time. The long scheduled
wait at London Bridge meant we caught up and joined the GN line on
time. But this is an example of how easily delays from one side of the
Thames can be exported to the other.

The train itself was almost empty, with about half the passengers
taking no special interest in the new route, but the others rushing
round with cameras. There were no announcements about it being the
first run, but a chap came round as we passed through the Canal
Tunnels handing out free celebratory Thameslink cupcakes. Most of the
pax seemed to get off at Finsbury Park.

Here's a few pictures. I managed to snatch one inside the Canal
Tunnel, and noticed that the concrete tunnel linings say 'CTRL',
presumably because the tunnels were built as part of the CTRL project,
and perhaps the tunnel linings came from the same factory?

https://www.flickr.com/photos/recliner/albums/72157693123465884