Perhaps some clarification -
There are trains form Luzern that go directly to Langnau im Emmental.
You can see the schedule in the timetable, and also see whether changes are needed.
On a random date in June, there are trains at xx16 and xx57.
The trains at xx16 are local/commuter trains, in this case the S6 and make many stops. They take one hour and 5 minutes to get to Langnau.
The RE ( RegioExpress) at XX57 takes 55 minutes.
Neither one requires a change of train.
The Show Dairy -
The Show Dairy in Affoltern im Emmental requires a bus. Their are two lines that you can use. One line connects train stations at Sumiswald-Grünen and Huttwil, and stops at the former train station at Affoltern Weir, in the valley. From Affoltern Weir station, you catch a second line which goes up the hill to Affoltern i.E; get of at bus stop Affoltern i.e, Dorf. (Dorf means village).
That bus continues to Hasle-Rüegsau train station.
The simplest route best route is to catch that bus in the other direction. Pick it up at Hasle Rüegsau . To do that will require at least one change of trains. That could be at Langnau or at Konolfingen. Schedules would dictate which one you choose.
Here is one option to do that -
Take the xx57 from Luzern direction Bern, get off at Konolfingen, and change to the train for Burgdrof, which stops at Hasle Rüegsau. Get off the train at Hasle-Rüegsau and ride up to Affolter, i.E., Dorf. The connection at Konolfingen is about 30 minutes, so that is not a fast route.
There are quite a few options for trains and buses in that region. The network is complicated. If you are in Langnau, the train from Langnau to Burgdorf stops at Hasle Rüegsau.
Also, that same train stops at Ramsei, where you can catch a train to Sumiswald-Grünen, then a bus to Affoltern-Weir and the bus from Afoltern-Weir to Affoltern i.E.
I routinely get confused when I am making connections around that area. I have learned to watch the schedule boards and trains very carefully. I'd suggest that you ask the train station staff at Luzern or Langnau or Konolfingen to print out itineraries for you, . It is important to watch the timings of trains closely at some of those stations....particularly, Langnau and Konolfingen, because there are often a couple of trains that arrive and depart close to the same times ( to allow various connections.)
This map can help you visualize the routes and connecting points..
Zoom in and you can see the train lines. Under the menu for Points of Interest/Traffic, you can overlay icons for the transport stops. Zoom in and mouse over an icon, and you get a brief schedule of trains or buses stopping there , in the near future.
The show dairy ( signs will say "Schaukäserei") is a very short walk from the bus stop. It has a nice restaurant, featuring cheese dishes, not surprisingly.
This thread may interest you. It includes a few pictures from the show-dairy at Affoltern.
Scroll down on the second page to the post on April 16, at 3:47 PM.