List of Dream Theater Songs and Their Tunings

[Metro]

Watching a few videos, it's hard to tell since people never zoom in on the bass player when filming (welcome to my eternal struggle), but it looks like he's using the same tuning as he does on As I Am (CEADGC). Hopefully someone gets better footage of John Myung specifically on this tour to confirm, but this is the best I can tell for now.

I agree. It even looks like the same blue bass he was using for As I Am last year.

[DT89]

JP confirmed that its Drop Bb tuning in this video
https://youtu.be/H2vy5dPd274?si=VC86_iCPFWSCr71M

Although the captions for the video say "raw deep loud" tuning 

Boom!

[doctormeat]

In the Arms of Morpheus
Guitar: F# B E A D G B E (Standard, 8-String)
Intro has an acoustic guitar tuned to E standard with a capo on the 8th fret
Bass: C# F# B E A D (Standard, 6-string w/ capo on the 2nd Fret)

A Broken Man
Guitar: D G C F A D (D Standard, 6-string)
Bass:

Dead Asleep
Guitar: Bb F Bb Eb G C (Drop Bb, 6-string)
Intro has an acoustic guitar tuned to Drop D with a capo on the 8th fret
Bass:

Tentatively, I want to say that JM is in B D A D G C for A Broken Man and is in Bb Eb Ab Db Gb B for Dead Asleep. That could be a good starting point until we see him play those live if you'd like to add that. Also, (and I could be wrong) I've transcribed In the Arms of Morpheus and don't think he used a capo on that one like he did on Awaken the Master (so just standard).

[GalacticGuitarist87]

Dead Asleep definitely sounds like it is a baritone guitar if I may add, not just a six string 25.5 scale, it's rather chunky sounding.