Post by Basil Jet
Does anyone know why the bridge carrying the LU eastbound lines (left)
is so much higher than the bridge carrying the LU westbound lines
(centre), and why the Chiltern lines (right) are slightly lower again.
The lines look to be roughly level with each other at Kilburn station to
the east and at Forty Avenue to the west, which are the next nearest
places where the lines go over roads.
Looking at birdseye view on Bing.com/maps I note that there are spans
under all 6 lines and another span that has no lines on it. That
seems to be the one at the left of your google view. I deduce that
the Chiltern line and westbound LU lines, the southernmost 4 lines,
share the same level, all being 19th century lines. (by the Met and
Great Central Railway). The eastbound pair were probably added later
by the Met with just a little more road clearance. Why the most
northerly span with the greatest road clearance and no rails was
built, or when, I have no idea., Did it ever have rails?
The other bridges you mention - is the road clearance more generous?