Site of Chawsey Weir?  Fred Thacker:

[Chawsey Weir] probably stood at the little islands just above Norcot Scours

1580 & 1585:  Bishop mentions Chawsey Weir.

1859: The Thames, Mr & Mrs Hall

The line of the Great Western Railway is in sight almost all the way between Pangbourne and Reading, and, for the most part, in close proximity to the river. About Purley, the tall wooded banks approach each other, and forming now and then close umbrageous scenes of exquisite beauty.

1881: George Leslie, "Our River" -

The stream soon begins to run with a will above this spot, and the great Western, which has been threatening for some time, here closes up to the river;  this is not of much consequence, however, as far as the scenery is concerned, for the railway very soon dives into a deep cutting, becoming the very opposite of what a good little boy should be, namely, “heard but not seen”.

Poplar Island

1889: Jerome K Jerome -

The railway rather spoils it near Tilehurst

Kentwood Deeps

The Roebuck

aka "Beethoven's Bistro", Left Bank, steps up over railway
1881: George Leslie, "Our River" -

The river narrows up into a gorge as the Roebuck is reached.  This quaint little inn has not much to recommend it, beyond its convenient station as a resting-place.  Its situation is peculiar, the house being on the further side of the railway, with steps up and down to reach it from the river.

The towpath changed sides twice inside a quarter of a mile due to an awkward landowner.  There were two ferries:

Site of Roebuck Ferry

1794:  Ferry established to avoid towing past Purley Farm
1881: George Leslie, "Our River" -

I have a great affection for horse-boats, those clumsy things that are found all the way up the river wherever the tow-path changes sides.  I suppose I like them because they are akin to the punt.  They are very picturesque, and with the little house that is sometimes seen near them, for the ferryman to live in, form good objects for the foreground of a sketch;  groups of children are often seen hanging about, adding very much to the beauty of the composition.  There are two of these ferry boats just above the Roebuck Inn, and the second one affords a capital platform  for bathing purposes, as the water is deep and very clear and free from weeds, better as a bathing-place than the weirs and lashers so often used, which are at all times exceedingly dangerous, on account of the back sucks, old sunken piles, &c.
Here the river takes a bend away from the railway.

At the end of this reach as the bend which marks Purley is approached the river comes right up to the great wall of the railway. You will be amused to note a post box at well above head height in this wall. Is this installation art? Or did a towpath once go along here? Even so it would be a strange place for a post box!