EMI 1936 Emitron Television
Camera Side view.
There is a good description of the "Marconi-EMI television equipment
at the Alexandra Palace" in the journal of the Television Society,
June 1936 page 169.
This states that there were 6 Emitron cameras available,
presumably 3 in each studio plus the 2 telecine machines.
In 1937 and 1938 when the OB units, MCR1 & MCR2, were made the number
would have increased to 12, 6 plus 3 in each OB unit.