In message , at 16:33:58 on Mon, 24 Jun
2019, Recliner remarked:

The only part that wasn't in daylight was from Earl Court station to
outside {High Street Ken}.

During the steam era, that was all in the open (it was only built over in
the 1950s, for the West London Air Terminal).

When was Kelso Place built, that and the surrounding streets are above
the line.

Cutting out the stops, from Earls Court station about halfway along the
platform we were moving under cover for 20sec, out in the open for
20sec, darkness again for 30sec, sidings for 30sec and then in darkness
again (a proper tunnel!) for 1min 25sec.

All timings to nearest 2sec. We weren't much above walking pace a lot of
the time.

You would also have gone through a different covered section between Earls
Court and Barons Court, under the former exhibition hall. That too would
have been open in the steam era, and for some decades thereafter (the
exhibition hall was built over the tracks in 1935-7).

I wasn't paying attention to the approach to Earls Court Station, but
the line immediately west of the station is open-air and it ventilates
the shed quite well.
--
Roland Perry