(Updated to fix name-confusion)
Here’s the deal:
and it looks like it is possible to follow this railway fairly closely on bike, at least up to Skölsta.
From there on, I am not so certain any longer, but I will try to find a good route this week.
What I have not told you yet is this: In the weekends in summer, a regular passenger service is run on this railway. Some of the trains running the stretch are really great-looking Steam trains. The organisation running the service has six of them in reserve.
And I have just decided that I want try to race one of them next Saturday.
I am not sure how fast they go at max speed. Steam trains are not necessarily all that slow, so it is entirely probable that I simply cannot keep up. The biking route is also slightly longer. After coming out of Uppsala for instance, Lennakatten goes straight through the forest, while I have to take a path around it. And after Skölsta, there are probably cycle paths that I can follow, but I will have to check out how they go.
On the other hand, the locomotive will be burdened by 4-5 wagons full of passengers, and it has to stop at stations on the way.
So it may not be completely ridiculous.
But the point is: I intend to find out.
As a little extra information, the Lennakatten railway is actually getting expanded. We just had a new bridge installed not many days ago.