
The table below shows the required locking positions.
A lever number or name followed by 'N' means the lever must be in normal position, followed by 'R' means the lever must be in reversed position.

Lever no. followed by * indicates locking for flank protection or overlap protection. Note that the position of these levers may sometimes be either normal or reverse, but the lever is locked in that position when the signal is cleared.
Signals in opposite direction giving direct access to the route as indicated must always be at danger and are not explicitly listed in the table below. Signals in opposite direction which do not give direct access but must be at danger for overlap protection are included, and are indicated by *.

Column "call on" indicates if the signal can be cleared on occupied track. 
When signal requires 'caution', the signal must be kept at danger until the speed of the train is sufficiently reduced (approx. 10 mph).

------------------------------------------------------------------
Sign|  Route to | Endsignal | Req levers |Call On | Notes
------------------------------------------------------------------
    |           |           |            |        |  
        Chippenham East                                
    |           |           |            |        |  
  A |     -     |     -     |01R,02R,06R |        | Distant
    |           |           |            |        |  
 01 | Down Main |    02     |13N,18N,21N,|        | Caution
    |           |           |22N,23N,26N,|        |  if 02N
    |           |           | 12N*,19N*  |        |  
    |           |           |            |        |  
    |           |           |Also 043N*  |        |  
    |           |           |with 042N   |        |  
    |           |           |            |        |  
 02 | Down Main |    06     |13N,18N,21N,|        | Caution
    |           |           |22N,23N,26N,|        |  if 06N
    |           |           | 042N,046N, |        |  
    |           |           | 043N*,044N*|        |  
    |           |           |            |        |  
 03 |Calne Brnch|    04     |20R,22N,21R |        | Caution
    |           |           |            |        |  if 04N
    |           |           |Also 043N*  |        |  
    |           |           |with 042N   |        |  
    |           |           |            |        |  
 04 | Down Main |    06     |20R,22N,21R,|        | Caution
    |           |           | 042N,046N, |        |  if 06N
    |           |           | 043N*,044N*|        |  
    |           |           |            |        |  
 05 | Down Main |    06     |13R,18N,21N,|        |  
    |           |           |22N,23N,26N |        |  
    |           |           |            |        |  
 06 | Down Main |   125     | 042N,046N, | Note   | Caution if
    |           |           |   109N*    |        |  Call On
    |           |           |            |        |  
 11 |  Up Main  |    17     |    15N     |        |  
    |           |           |            |        |  
 12 |Down Ref Sd|     -     |    13R     | Yes    |  
    |           |           |            |        |  
 14 |Up Sdg Loop|     -     |    15R     |        |  
    |           |           |            |        |  
 16 |  Up Main  |    56     |    15R     |        |  
    |           |           |            |        |  
 17 |  Up Main  |    25     |18N,23N,24R |        |  
    | Down Main |    06     |18R,21N,22N,|        |  
    |           |           |  23N,26N   |        |  
    |           |           |            |        |  
 19 | Down Main |    12     |    18N     |        |  
    |  Up Main  |    56     |  15N,18R   |        |  
    |           |           |            |        |  
 25 |  Up Main  |    28     |    26N     |        |  
    |Goods Shed |     -     |    26R     |        |  
    |           |           |            |        |  
 27 |  Up Main  |   54/57   |    26R     |        |  
    |           |           |            |        |  
 28 |  Up Main  |    34     |    29N     |        | See Note 
    |Up Stat Sdg|     -     |29R,68N,32N | Yes    |  
    | Up Siding |     -     |  29R,68R   |        |  
    |           |           |            |        |  
 30 |  Up Main  |   54/57   |  29R,26N   |        |  
    |Up Sdg Loop|     -     |    29N     |        |  
    |           |           |            |        |  
 31 |  Up Main  |   116     |    32N     | Yes    |  
    |Up Stat Sdg|     -     |    32R     | Yes    |  
    |           |           |            |        |  
 33 |  Up Main  |   54/57   |32R,35N,29N,|        |  
    |           |           |    26N     |        |  
    |Up Stat Sdg|    30     |  32N,68N   |        |  
    |           |           |            |        |  
 34 |  Up Main  |    31     |    35N     |        |  
    | Calne Bay |     -     |35R,36R,42N,| Yes    |  
    |           |           |    39N     |        |  
    | Middle Sdg|     -     |35R,36R,42N,| Yes    |  
    |           |           |    39R     |        |  
    | Down Main |   125     |35R,36R,42R,| Yes    |  
    |           |           |    46N     |        |  
    |           |           |            |        |  
 38 | Calne Bay |     -     |37R,35N,36R,| Yes    |  
    |           |           |  42N,39N   |        |  
    | Middle Sdg|     -     |37R,35N,36R,| Yes    |  
    |           |           |  42N,39R   |        |  
    | Down Main |   125     |37R,35N,36R,| Yes    |  
    |           |           |  42R,46N   |        |  
    |           |           |            |        |  
 40 | Calne Bay |   53/58   |  39R,42N   |        |  
    |           |           |            |        |  
 41 |Up Stat Sdg|     -     |29N,68N,32N | Yes    |  
    | Up Siding |     -     |  29N,68R   |        |  
    |           |           |            |        |  
 43 | Down Main |    19     |42N,26N,21N,|        |  
    |           |           |  22N,23N,  |        |  
    |           |           | 01N*,02N*, |        |  
    |           |           | 03N*,04N*  |        |  
    | Calne Bay |   53/58   |    43R     |        |  
    |           |           |            |        |  
 44 | Down Main |    43     |    46N,    |        |  
    |           |           | 02N*,04N*  |        |  
    |           |           |            |        |  
 45 | Down Main |   126     |    46R     | Yes    |  
    |           |           |            |        |  
 47 | Goods Shed|     -     |    46R     |        |  
    |           |           |            |        |  
 53 |Reversal Sd|     -     |35N,36R,37R | Yes    |  
    |           |           |            |        |  
 54 |Calne Brnch|  Calne    | 20R,22R,   |        | LC
    |           |           | 23R,24R    |        | See Note
    |           |           |            |        |  
 56 |  Up Main  |Langley Cr |            |        | LC
    |           |           |            |        |  
 57 |  Up Main  |    57     |15N,18N,23N,|        | Caution
    |           |           |    24R     |        |  if 56N
    |           |           |            |        | See Note
    |           |           |            |        |  
 58 |  Up Main  |   54/57   |35R,36R,29N,|        |  
    |           |           |    26N     |        |  
    |           |           |            |        |  
 59 | Calne Bay |   53/58   |  29N,42N   |        |  
    |           |           |            |        |  
 62 |  Up Main  |   54/57   |26N,29N,35N,|        | Caution
    |           |           |    32N     |        |  if 57N
    |           |           |            |        |  
 65 |  Up Main  |     -     |62N,57N,56N |        | Distant
    |           |           |            |        | Slotted by
    |           |           |            |        |  103
    |           |           |            |        |  
    |           |           |            |        |  
        Chippenham West                                
    |           |           |            |        |  
101 |  Up Main  |     -     | 102R,103R  |        | Distant
    |           |           |            |        | Slotted by
    |           |           |            |        |  65
    |           |           |            |        |  
102 |  Up Main  |   103     |111N*,115N*,|        | Caution if
    |           |           |   116N*    |        |  103N
    |           |           |            |        |  
103 |  Up Main  |    62     | 111N,115N  |        | Section B4
    |           |           | 29N*,32N*, |        |  must be 
    |           |           |    35N*    |        |  clear 
    |           |           |            |        |  
106 |  Down Bay |     -     | 107R,109N, |  Yes   |  
    |           |           | 110R,111N, |        |  
    |           |           |   112N     |        |  
    |  Up Main  |    62     | 107R,111R, |  Yes   |  
    |           |           | 112N,115N  |        |  
    |           |           |            |        |  
108 | Down Main |   44/47   | 109N,110R  |  Yes   |  
    | Down Bay  |     -     | 109R,110R, |  Yes   |  
    |           |           |   112N     |        |  
    |  Up Main  |    62     | 109R,111R, |  Yes   |  
    |           |           | 112R,115N  |        |  
    |           |           |            |        |  
113 | Down Sdg  |     -     | 107R,111R, |  Yes   |  
    |           |           | 112N,102N* |        |  
    | Down Main |   123     | 109R,111R, |        |  
    |           |           | 112R,102N* |        |  
    |           |           |            |        |  
114 |  Up Main  |    62     |   115R     |        |  
    |           |           |            |        |  
116 |  Up Main  |   113     | 115N,102N* |        |  
    |Up Platf Sd|     -     | 115R,102N* |        |  
    |           |           |            |        |  
122 | Down Sdg  |     -     | 107R,109N, |  Yes   |  
    |           |           | 110R,111N, |        |  
    |           |           |   112N     |        |  
    |           |           |            |        |  
123 | Down Main |Thingley Jn|            |        | LC
    |           |           |            |        |  
124 | Down Main |   123     | 109R,110R, |        |  
    |           |           | 112N,107N  |        |  
    |           |           |            |        |  
125 | Down Main |   123     | 109N,110R  |        | Caution if
    |           |           |            |        |  123N
    |           |           |            |        | See Note
    |           |           |            |        |  
126 | Down Main |     -     | 123R,125R  |        | Distant
    |           |           |            |        |  Slotted by
    |           |           |            |        |  06
    |           |           |            |        |  
127 | Down Main |     -     | 123R,125R, |        | Distant
    |           |           |   126R     |        |  Slotted by
    |           |           |            |        |  02 and 06
    |           |           |            |        |  

Notes : 
Signal 6 :
Call On only allowed when required for (shunt) engine to
attach to train.
It is not allowed to take two trains into the platform.
Also, signal 6 can only be cleared to occupied track if the approaching
train is occupying section A4.

Signal 28 :
With 26N, needs 57N and 54N.

Signal 54 :
With 26N, needs 28N.

Signal 57 :
Caution is only required for trains due for Langley Crossing,
not for local shunt moves.
With 26N, needs 28N.

Signal 125 :
Caution is only required for trains due for Thingley Junction,
not for local shunt moves.

Signal 101 :

Additional locking requirements :

-----------------------
 position  | requires
-----------------------
           |           
   109     | 112N OR 111R, 112R
   111     | 112N OR 109R, 112R
           |           

Note : 
Sequence to set switches from Down Main to Up Main is :
109 - 112 - 111, resetting must be done in reverse order.
Sequence to set switches from Up Main to Down Main is :
111 - 112 - 109, resetting must be done in reverse order.

    
FPL :

--------------------------
    FPL    | locks switch
--------------------------
           |    
    20     |    22
    24     |    23
    36     |    35
   110     |   109
           |    
