There are 3 options I’d consider. All times per SBB app

Option 1 :

• Luzern - Arth-Goldau 17:39 - 18:11 easy connection from track 6 to track 3
• Arth-Goldau - Milano Centrale 18:18 - 20:50

Seat reservation for the second train : 9 x 11€

Option 2 :

• Luzern - Arth-Goldau 17:39 - 18:11
• Arth-Goldau - Lugano 18:18 - 19:30
• Lugano - Milano Centrale 20:02 - 21:17

Option 3 :

• Luzern - Arth-Goldau 17:18 - 17:45 same platform connection (easy)
• Arth-Goldau - Lugano 17:49 - 18:58 guaranteed connection for a few min delay, can be stressful for 9 people because you need to go down a ramp and up another one
• Lugano - Milano Centrale 19:02 - 20:17

Options 2 and 3 do not require any reservations so you can decide on the day which one you’d like to take. You’d arrive at 16:49 from Engelberg.

Btw Rail Planner doesn’t show connections under 5 minutes.

Hi ,

Option 2: I need to add 3 journeys correct? because i didn't find this journey none of the apps( Eurorail/sbb/oebb)

For example,

If I had taken14:18pm Luzern-Mliano P Garibaldi and reach Milano at 18:17 via Lugano , simple i just need to add this journey on respective travel day . 

I just wanted to check this connection on Sbb and oebb but its showing ticket is not available on Oebb website. ? also when I tried to save journey on oebb website instead of eurorail its asked to reserve seat for 3 euros to get guaranteed seat. Will seats will be available without adding extra options as well?

attached screenshots . Please check it

That's what ÖBB show when they can't sell a ticket for the journey. Also, your screenshot shows only trains that cannot be reserved.

Seat reservations in Switzerland are sometimes possible, but are a waste of money. Just board and find a seat.

so which option do I need to select ?

shall i simply add journey on eurorail app even though its different from oebb ?

If you travel without reservations, then you just add your journey to the rail planner app. If you don't find the trains you need, then try:

• Go into the filter and reduce the minimum change time
• Use a “via” station if you need to force the route
• Request the trains you need separately.
• If you still don't find a train, then add it manually into the app.

I think my question was not clear.

what does it mean by ticket not available in Oebb website ? I added my journeys on eurorail app to travel from Luzern- milano via Lugano.

but i just cross checked timings on Sbb and oebb. but lugano-mialno its shows no tickets available. what does it mean ? i wont get seats to sit because we are 9 people. just wanted to be mindful before booking anything.. apologies for too many questions

Tickets not available on ÖBB means that seats cannot be reserved on that train. 

Simply show early and you'll find seats :)

Need a suggestion. 

if i take 08:10am train from lucerne -engelberg to cover Mt titlis will i be able to catch 16:18 train Luzern-Lugano ? 

Luzern 16:18pm - lugano 17:58

Lugano 19:02- Milano P Garibaldi 20:32 ( I added this journeys on the eurorail app)

or better to go for paragliding activity at Interlaken ?

Please guide me..

Titlis is totally doable yes, you need to leave the top at around 2pm to make the 3pm train

Interlaken is too far away.

The 19:02 train arrives at 20:17 in Milano Centrale, the main railway station. Then it is a 15-min walk to Porta Garibaldi if needed

You are the best you always helped me.. 

Just for your Information: The 16:18 Train from Lucerne is one of the few ones on this route, that runs directly to Milano Centrale (without the change in Lugano):

Arrival at Milano Centrale at 19.50.

But it’s chargeble?

Yes for the part in Italy you need to add a 11€ seat reservation (on tickets.oebb.at) for this one

Yeah I checked this connection but it’s 13 euro for seat reservation so booked the one which I had shared earlier . 
 

is that train connection is good if we go for a Mt Titlis trip ? We will take earliest train to Engelberg . 

All connections are good. The hourly train from Engelberg arrives at xx:49