Would it be possible to build Babbage's Difference Engine or Analytical Engine in the mid 1870's with existing manufacturing technology. Specifically, as a government project, with money available even if it will never turn a profit. And if built, how much ongoing repair and maintenance would the beastie need to KEEP working? Obviously the Analytical Engine is more complex, so assume that both are going to be built if practical. The US Government wants it badly enough that money WILL be forthcoming--and if a new railroad or ironclad needs to be sacrificed, so be it.
How much time would each machine spend working, as opposed to being maintained and repaired?