Great Western Short Coaches

The Lewis Classification System

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John Lewis wrote in Model Railway Constructor annual 1981 an article called “GWR Dean Period Coaches”. This article enables the historian distinguish between the different phases of Dean's coaches and gives a logical code to each design. Throughout these pages I often refer to the Lewis Classification of a coach design to help distinguish between different designs. Below is a summary of the meaning of each letter in the code.

  C A E 12 C N  
C - Clerestory Roof \_|     |  |  |  | |__/ B - Broad Gauge Body Width - 10' 0¾"
L - Low Roof /   |  |  |  | N - Normal Body Width - 8' 0¾"
      |  |  |  | \ W - Wide Body Width - 8' 6¾"
Only used if first letter is C \__  |  |  |    
A - Single Arc Top Roof  |    |  |  \ __/ Optional letter
E - Elliptic Top Roof /    |  |   C - Converted from Broad to Standard Gauge Body
       |  |   M - Metropolitan style body sides
A - Single Arc Main Roof \__   __ /  |   \ T - Transitional style body sides
E - Elliptic Main Roof /      |      
         \ ___ __/ 0 - no eaves panel above compartment windows
            4, 7, 9, 12 - height in inches of panel above compartment window

The first 2 or 3 letters define the roof type. The drawing below illustrates four of the five main types of roof style of Dean period coaches, there was also a CEE style (but only 4 short coaches were built with this type of roof).


Eaves Panel
The number in the middle of the code relates to the height of the eaves panel and this can often be the hardest part of the code to determine when looking at an unknown photograph. The drawing below illustrates all the eaves panel variations together with the doors that they were used with. Notice that the 0, 4" & 9" were slightly shorter than the others. Also notice that there are different numbers of lines across the ventilators in the doors.


Optional Letter
This drawing also illustrates the difference between the Normal body side style where the door and compartment windows are the same height; the Transitional body side style where the compartment windows are taller than the door window; and the Metropolitan body side style where the door ventilator is semi-circular. Note that there is no code letter for the Normal body side style, whereas T is required for Transitional and M is required for Metropolitan body side styles.

The other optional code letter is C. This denotes a coach that has been converted to standard gauge from a broad gauge coach.


Body Width
The last letter of the code relates to the body width. Most GWR short coaches were 8' 0¾" wide and had 5 vertical panels on the ends, as illustrated in the top drawing above. For these coaches the code letter is N.

Broad Gauge coaches were either normal 8' 0¾" wide bodies but mounted on a broad gauge chassis, or were 10' 0¾" wide and had 7 vertical panels on the ends. The code letter for the latter coaches is B. When these coaches were converted to run on the standard gauge they became 8' 0¾" wide and had 5 vertical panels on the ends. The code letters for these coaches is CN.

From 1884 some coaches were built an extra 6" wider than the normal width. The code letter for these coaches is W. Initally the only wide coaches built were for the London Metropolitan line services. The code letters for these coaches is MW. Later, other coaches where built 8' 6¾" wide, although all were bogie coaches with the exception of the odd saloon. Most wide coaches had 6 vertical panels on the coach ends, but at least the first 8 built only had 5 panels.



Lewis Classification Codes Relavent to GWR Short Coaches

Not all of the possible permutations ever existed. Of those that were built, some were only built as bogie coaches which are not covered in these web pages. The codes of interest here are:

Low Roof Clerestory Roof