Hello kildaremark

From research I did some years ago at Kew, the numbering of TMBs went up to 114, although there were some gaps, notably in the 50s and 70s. I'm inclined to agree with Kevin that numbers in the 300s and 400s were not sequential.

When the allocation of TMBs was formalised in mid-1916, brigade TMBs were ligt, equipped with the Stokes, and were manned predominantly by infantrymen. Medium and heavy TMBs, at divisional level, were regarded as units of the RFA and RGA respectively, though this did not mean that there was no mixture of RFA and RGA men among them - in fact, that seems to have been quite common. The heavy TMBs were generally cosolidated as Corps-level units in 1918.

Roytoner

Here are the original War Establishments for various types of TMB. There were only minor changes thereafter:

September 1915 Trench Mortar Battery (4 mortars of the same type)

2 Officers, 1 Serjeant, 4 Corporals or Lance-Corporals, 16 Privates, 2 Batmen.

August 1916 Light Trench Mortar Battery (2 sections, each 4 x 3" Stokes mortars)

Captain, 3 Subalterns, 2 Serjeants, 8 Corporals or Lance-Corporals, 32 Privates, 4 Batmen.

August 1916 Medium Trench Mortar Battery (4 x 2" mortars)

2 Officers, 1 Serjeant, 4 Corporals or Bombardiers, 16 Privates, 2 Batmen.

August 1916 Heavy Trench Mortar Battery (4 x 9.45" mortars)

Captain, 2 Subalterns, 3 Serjeants, 1 Fitter, 4 Corporals, 4 Bombardiers, 47 Gunners (incl 3 telephonists), 2 Orderlies, 1 Clerk, 1 Cook, 3 Batmen.

Ron

thank you very much Ron, appreciate it

Source: Trench mortar batteries