|1941 Aerail Photo from ILHAP|
HAER IL-31 has a pictures of the old dam and the two old truss bridges just downstream from it. HAER also has documented the construction of the new dam as IL-32. The railroad bridge has been abandoned and removed while the US-67 bridge has been replaced with a cable stay bridge.
[WikipediaOld, WikipediaNew, John Weeks III]
|Mike O'Neal posted|
Park downtown Alton the train bridge is gone and a new Alton bridge is in place today the train bridge would open and close on the lock and Dan 26 to let the boats go through. The dam 26 is move down the river about a haft mile.
[This is just one of the construction photos from HAER IL-31]
|Dave Hall -> RAILROAD HISTORY BUFFS OF ILLINOIS|
To all the folks in Jersey and Madison counties,,check out this photo of Chautauqua from the bluffs facing east,,notice the river level before the lock and dam in Alton,Illinois
I include a satellite image of the main structures of the new dam because it caught a 15-barge tow entering the main lock.
|By J Clear (talk) - I created this work entirely by myself., CC BY-SA 3.0, Link|
Lock and Dam No. 26R represent the present state of the art in river navigation control works. The basic components of the installation are comparable to those utilized in the 1930s. The most striking difference between the older installations and Lock and Dam No. 26R is the immense size of the new structures. The significance of the new installation is not limited to its size. Throughout the design and construction process, the Corps of Engineers and the various contractors have engaged in an extensive program of computer-assisted design, testing, and evaluation. These sophisticated studies represent perhaps the most significant difference between the older structures and Lock and Dam No. 26(R).The condition of those gates indicates designing with "engineer's gut feeling" is better than design by computer.
The upstream gate of the 1200' lock is a lift-gate instead of a miter gate. So this joins the list of the the Keokuk (#19) Lock and Lockport Lock as the three dams I know of that use a lift gate instead of a miter gate for the upstream side. I still have not found out why a lift gate would be used.