I heve recently read that, about 1900, many of the original Canal Line bridges were replaced in order to support heavier trains. It is entirely likely that this was one of the new bridges. The heavy brownstone blocks come from quarries in Portland, Conn., alongside the Connecticut River about 14 miles to the east, from where they can be barged down-stream to Brooklyn, Boston and beyond, for its popular use in the facades of 19th Century town-houses. It would have been (relatively) easy to bring them to New Haven, and straight up the existing rails.
About 17,000 years ago, as the glaciers melted back, the Tenmile being a tributary of the larger Quinnipiac River, which at some point had become naturally dammed, in neighboring Meriden, leaving this whole area long under the waters of large Glacial Lake Southington, into which very great quantities of sand and clay were deposited. The presence of rather yielding materials necessitated the use of many driven pilings underneath the supporting structures of area bridges over these rivers. This would have been a LOT easier to do in 1900 than in 1848. I also suspect that considerable track re-grading may have been done along here, to raise the track above occasional contemporary flooding, as the area is rather flat, and an original Farmington Canal culvert over the Tenmile (1828, also a stone arch bridge) acts as an impediment to rapid draining in the area, as does a 1931 concrete arch bridge below that, three arches in a little more than a mile!