The accompanying photo shows the expression pneumatics for a Welte T100
player installed in a Mason & Hamlin upright. The question is, has this
configuration of pneumatics on a 'plank' been used on other pianos?

Of the nine Mason & Hamlin upright T100 pianos I have located, this is
the only one with this 'plank' configuration. On all the other pianos
the pneumatics were mounted on an iron frame.

The M&H and Welte numbers are as follows:

M&H S/N 22580
Welte Stack S/N 22580
M&H Model 756
Welte Number Op W142
M&H Plate Casting Number 31p, M7, 7 10 13
Key Action S/N 8 (12/4/13 in pencil)

Richard Cardwell
Palo Alto, California

 [ Jody fixed a problem that made the attached image un-displayable. See
 [ Welte T100 Unusual Expression Pneumatic Configuration
 [ https://www.mmdigest.com/Attachments/21/09/12/210912_103507_Welte%20'Plank'.jpeg