From  The Rule Book  (1922) : Rule No.60

Stationary Signals At Douglas Station

The Signal Cabin is situated on the lend hand side going from the Station and is 71 yards west of the Platform for the Port Erin Line Traffic.

The Distant Signal on the Peel Line is 675 yards yard west of the Cabin.

The Distant Signal on the Port Erin Line is 675 yards west of the Cabin.

The Outer Home Signal on the Peel Lineis the arm o the left hand side of the post 299 yards west of the Cabin.

The Outer Home Signal on the Port Erin Line is an arm fixed on a bracket on the last-named Signal Post, being the arm nearest to the Port Erin Line, 299 yards west of the Cabin.

The Home Signal on the Peel Line for Trains running into No.3 Line is the top arm of the left hand side of the bracket nearest to the Water Tank, and affixed to the Tank House, 110 yards west of the Cabin.

The Home Signal on the Peel Line for Trains running into No.5 Line is the middle arm of the left hand side of the bracket nearest to the Water Tank, and affixed to the Tank House, 110 yards west of the Cabin.

The Home Signal on the Peel Line for Trains running into the Goods Lines is the bottom arm o the left hand side of the bracket nearest to the Water Tank, and affixed to the Tank House, 110 yards west of the Cabin and is distinguished by having a ring shown on the arm.

The Home Signal on the Port Erin Line for Trains running into No.5 Line is the top arm of the left hand side of the bracket nearest to the Railway on the Tank House, 110 yards west of the Cabin.

The Home Signal on the Port Erin Line for Trains running into the Goods Line is the bottom arm on the left hand side of the bracket nearest the Railway on the Tank House, and affixed to the Tank House, 110 yards west of the Cabin and distinguished by showing a ring on the arm.

The Starting Signal for Trains going from No.2 Line (Peel Departures) to Peel is situated at the end of the Peel Platform, 74 yards east of the Cabin.

The Starting Signal for Trains going from No.6 Line (Port Erin Departures) to Port Erin is situated at the end of the Port Erin Platform, 71 yards east of the Cabin.

The Departing Signal for Trains going from No.5 and No.6 Lines or from the Goods Line, is situated on the left hand side of the left hand bracket post, 29 yards west of the Cabin.

The Starting Signal for Trains going to Peel from No.6 Line or from the Goods Line, is the arm on the left hand side of the right hand bracket post, 29 yards west of the Cabin.

The Starting Signal for Trains leaving from No.8, 9, 10 or 11 Lines is the arm on a post situated 41 yards east of the Cabin, and is distinguished from other signals by having a ring shown on the arm.

There are Three Signals for Shunting purposes, which are distinguished from the other Signals by each having the letter “S” shown on the arm.  One is situated at the end of the Peel Platform, 65 yards yest of the Cabin, and is to be udd for letting a Train out of No.3 Line; another is situated near No.4 Line, 65 yards east of the Cabin, and is to be used for letting a train out of No.4 Line; and the other is situated near the end of the Port Erin Platform, 71 yards east of the Cabin, and is to be used for letting a Train out of No.5 Line.

There are Two Ground Signals also for Shunting purposes - one for letting a Train out of No.1 Line, and the other for letting a Train out of No.7 Line.

Note: A Green Light will be substituted for the White Light on all the Signal Posts at or connected with Douglas Station as an “All Clear Signal” at night; and unless the Green Light be shown Engine Drivers must treat the Signal as being at Danger.