Many locomotives on the Gloucestershire Warwickshire Railway carry a small, oval plate on the smokebox door, that usually comprises two numbers and a letter - for example, 81A. This is a code for the locomotive's 'home' shed and is a system adopted on nationalisation of the railways, perpetuating a system used by the LMS.

Following are the shed codes adopted for British Railways, Western Region (of which the present-day Gloucestershire Warwickshire Railway was one a part). You will notice that Gloucester (Horton Road) was 85B and Cheltenham Malvern Road was a sub-shed with its locomotives carrying the same shed code.

• 81A Old Oak Common
• 81B Slough
  • Marlow
  • Watlington
• 81C Southall
• 81D Reading
  • Henley-on-Thames
• 81E Didcot
• 81F Oxford
  • Fairford

• 82A Bristol (Bath Road)
  • Bath
  • Wells
  • Weston-super-Mare
  • Yatton
• 82B St. Philip's Marsh
• 82C Swindon
  • Chippenham
• 82D Westbury
  • Frome
• 82E Yeovil (Pen Mill);
  • Bristol (Barrow Road), 
• 82F Weymouth;
  • Bath (S&D), 
  • Radstock W. 
  • Highbridge E. 

• 83A Newton Abbot
  • Ashburton
  • Kingsbridge
• 83B Taunton
  • Bridgwater
• 83C Exeter
  • Tiverton Junction
• 83D Laira (Plymouth)
  • Launceston
• 83E St Blazey
  • Bodmin
  • Moorswater
• 83F Truro
• 83G Penzance
  • Helston
  • St Ives

• 84A Wolverhampton (Stafford Road)
• 84B Wolverhampton (Oxley)
• 84C Banbury
• 84D Leamington Spa
• 84E Tyseley
  • Stratford-on-Avon
• 84F Stourbridge Junction
• 84G Shrewsbury
  • Builth Road
  • Clee Hill
  • Craven Arms
  • Knighton, 
• 84H Wellington (Salop)
• 84J Croes Newydd
  • Bala
  • Penmaenpool
  • Trawsfynydd
• 84K Chester; Wrexham Rhosddu

• 85A Worcester
  • Evesham
  • Kingham 
• 85B Gloucester (Horton Road) 
  • Brimscombe
  • Cheltenham (Malvern Road)
  • Cirencester
  • Lydney
  • Tetbury
• 85C Hereford
  • Ledbury
  • Leominster
  • Ross-on-Wye
• 85D Kidderminster
• 85E Gloucester (Barnwood), (from 1958, ex LMR)
  • Tewkesbury 
  • Dursley, 
• 85F Bromsgrove
  • Redditch

• 86A Newport (Ebbw Junction)
• 86B Newport (Pill)
• 86C Cardiff (Canton)
• 86D Llantrisant
• 86E Severn Tunnel Junction
• 86F Tondu
• 86G Pontypool Road
• 86H Aberbeeg
• 86J Aberdare
• 86K Tredegar

• 87A Neath
  • Glyn Neath
  • Neath (N&B)
• 87B Duffryn Yard (Port Talbot)
• 87C Danygraig
• 87D Swansea East Dock
• 87E Landore (Swansea)
• 87F Llanelli
  • Burry Port
  • Pantyfynnon
• 87G Carmarthen
• 87H Neyland
  • Cardigan
  • Milford Haven
  • Pembroke Dock
  • Whitland
• 87J Goodwick (Fishguard)
• 87K Swansea (Victoria);
  • Swansea (Paxton St.)
  • Gurnos
  • Llandovery
  • Upper Bank

• 88A Cardiff (Cathays);
  • Radyr
• 88B Cardiff East Dock
• 88C Barry
• 88D Merthyr
  • Cae Harris
  • Dowlais Central
  • Rhymney
• 88E Abercynon
• 88F Treherbert
  • Ferndale 

• 89A Oswestry
  • Landiloes
  • Moat Lane
• 89B Brecon
• 89C Machynlleth
  • Aberayron
  • Aberystwyth
  • Aberystwyth (Vale of Rheidol narrow gauge)
  • Portmadoc
  • Pwllheli

References: The Observer's Book of Railway Locomotives of Britain, H C Casserley, revised edition 1960, Frederick Warne & Co. Ltd, London;
and Wikipedia