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London Midland and Scottish Railway Searchlight Signals


London Midland and Scottish railway searchlight signal

LMS searchlight junction signal



The London Midland and Scottish Railway used colour light signals in several places. Installations after 1932 used the multi lamp type of signals similar to the Southern Railway but initially in 1932 the LMS uniquely used a complex system of speed signalling with searchlight signals on the London suburban lines to Watford and Upminster (the 'New Lines' signalling) as well as a four mile section of 4-track main line at Mirfield (the 'Mirfield' signalling).

T
he signals are capable of displaying up to five main aspects for high speed:-
Junction signals can additionally signal medium speed aspects for Medium Clear, Medium Preliminary Caution and Medium Caution. Additional low speed indications for Call On and Take Siding (Slow Clear) could also be provided. Stop signals with inline heads were absolute and not to be passed at danger whereas Repeater signals with staggered bottom heads were Stop and Proceed when at danger.

While this signalling was installed initially by the LMS in 1932 it continued in use at Mirfield until 1970 with slight modifications and in North London until 1988. The configurations in the SC1 and shown below cover the period 1937-1988.

The SC1 can be configured for individual searchlight heads in order to operate these signals by setting CV38=8 (standard accessory protocol) or CV38=129 (extended accessory protocol). Complete masts can be configured by the use of CV38=136 (two home, stop or repeater signals) or CV38=137 (one junction signal) or the user defined settings for CV38=135 can be  used if required.

LMS signal masts are controlled according to the following tables:-



LMS 5-aspect Home searchlight signal operation table for CV38=8

Base

state

Base+1

state

Base+2

State

Base+3

State

Aspect

Reverse

Normal

Reverse

Normal

Red

Red

Normal

Reverse

Normal

Normal

Green

Reverse

Reverse

Normal

Normal

Yellow

Reverse

Reverse

Normal

Reverse

Yellow

Yellow

Normal

Reverse

Normal

Reverse

Yellow

Green

LMS 3-aspect Call-On searchlight signal operation table for CV38=8

Base

state

Base+1

state

Base+2

State

Base+3

State

Aspect

Reverse

Normal

Reverse

Normal

Red

Red

Normal

Reverse

Normal

Normal

Green

Reverse

Reverse

Normal

Normal

Yellow

Reverse

Normal

Normal

Reverse

Red

Mini Yellow


LMS searchlight signal operation table for CV38=136 or CV38=137

Aspect description

Aspect number

Junction Aspect display

Stop/Repeater aspect display

Stop

0

Red

Dark

Red

Red

 

(Dark)

Red

Red

Stop and Proceed

0

Red

Dark

Red

Red

 

(Dark)

Red

Red

Permissive

2

Red

Dark

Red

Small Yellow

 

-

Red

Small Yellow

Take Siding

 1

Red

Dark

Red

Small Green

 

-

Red

Small Green

Clear

15

Green

Dark

Red

Red

 

(Dark)

Green

Dark

Approach

10

Yellow

Dark

Red

Red

 

(Dark)

Yellow

Dark

Preliminary approach

11

Yellow

Yellow

Red

Red

 

Yellow

Yellow

Dark

Advance Approach

12

Yellow

Green

Red

Red

 

Yellow

Green

Dark

Medium Clear

9

Red

Dark

Green

Red

 

-

-

-

Medium Preliminary Approach

6

Red

Yellow

Yellow

Red

 

-

-

-

Medium Approach

5

Red

Dark

Yellow

Red

 

-

-

-

Unlit

16

Dark

Dark

Dark

Dark

 

(Dark)

Dark

Dark


*Lamps shown as (Dark) are not present on 3-aspect signals





LMS searchlight signal wiring diagrams


2x 3-aspect, 4-aspect or 5-aspect stop or repeater signal wiring diagram

London, Midland and Scottish Railway five aspect searchlight signal wiring diagram
* Note that for a 3-aspect signal the top yellow lamp is not required

2x 3-aspect stop signal with call-on wiring diagram

London, Midland and Scottish Railway three aspect searchlight signal with call-on wiring diagram

5-aspect junction searchlight wiring diagram

London, Midland and Scottish Railway 5 aspect searchlight signal wiring diagram
*Note that output H can either drive the Yellow Call on lamp or the Green take siding lamp but not both.

4-aspect junction searchlight wiring diagram

London, Midland and Scottish Railway Four aspect junction searchlight with call-on and take siding wiring diagram



The following CV38 settings are possible:-
For other configurations use CV38=135 and create a user defined definition.

In JMRI use DCC Signal Mast Decoder for CV38=135, CV38=138 and CV38=137. For CV38=8 in general use Double Output for the upper heads and Triple Output for the bottom head, Single Output can be used for any heads that can just display a single colour or dark. Visit the JMRI LMS-1932 signal system to see the available mast types.
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