The Swiss railssystem is an integrated system. You can find all itinaries and all other information on www.sbb.ch/en
For your trip from Interlaken to Lucerne input from "Interlaken Ost" to "Lucerne" via "Brünig-Hasliberg" and you will get the trains available.
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Yes normal regional trains ply the same route as the fabled Golden Pass trains about hourly or so from Lucerne to Interlaken-Ost - terminus because the narrow-gauge tracks end there. You can with a Swiss Pass just hop on these trains or easily buy a ticket - never a problem getting on and the scenery s of course the same as on the Golden Pass train sans domed observation 'panoramic' cars that to me are more hype than anything else.

Great sites for info on Swiss trains - www.swisstravelsystem.com; www.http://www.budgeteuropetravel.com/id3.html and www.ricksteves.com.

and yes the Brunig Pass route is infinitely prettier than the faster mainline route via Bern IMO.

Is there a standard train that runs from Interlaken to Luzern through the Brunig Pass? Best map showing standard train routes?>

try www.sbb.ch - Swiss Railways official site - they have a rail map that shows all the countries myriads of railways.

If you are in no real hurry to get to Interlaken then consider breaking your journey on the Brunig Pass route in Meiringen, where the train reverses and thus stands several minutes while engine in changed to front from what there then is in the back!

Meiringen, which gave its name to meringue! is a sweet regional town known for having on its outskirts Reichenbach Falls, where Sherlock Holems and Prof Moriarity tangled and one fell to his presumed death - from the wide viewing belvedere that is accessible by antique funicular - buses run there from Meringen or it is a mile or so walk if I recall correctly.

Put your bags in a Meringen station luggage locker.

the Brunig Pass Railway BTW is the only Swiss Federal Railways - the mainline national railway that uses cog-wheels to help climb prodigious ascents and help brake on prodigious descents - I love taking this route and hearing the cogs go down with a cranking noise and then hear the cog wheel as it rather noisily rumbles when being used.

I believe it is also the only Swiss Federal Railway line (SBB) to be narrow-gauged - tracks closer together which in mountainous areas with steep climbs is easier than a larger train on wider-gauged tracks.