THE SIGNAL BOX

PHOTO GALLERY

London & North Western Railway

HARROW No2

Opened: 1923

Closed: 1988

Location code: LM9/04

Harrow No2 box was, at first glance, not a very interesting location - controlling the Euston to Watford electric lines with automatic colour-light signalling. However, a closer study reveals a lot of historical interest and many original and unaltered features survived into recent years.

A general view of the layout at Harrow No2

This view, taken from the two reversing sidings shows the neat symmetry of the layout, featuring matching traps and a double-slip whilst the running lines pass either side.

Although the BR electric units were modified in the 1970's to not use the central return rail, this is retained as the line is also used by Bakerloo Line underground trains.


Harrow No2 signal boxThe box itself was of the LNWR's 1904 design, which was a development of their 1876 type (illustrated at Chester No4) embodying taller window sections and overhanging gable ends.

Harrow No2 was a late arrival, erected in 1923 when the reversing sidings were provided in anticipation of the introduction of electric multiple unit services on the New Line.


Signals at Harrow No2The signalling on the New Line was a curious mix of equipment. Colour light signalling was employed for running signals, capable of working completely automatically when the box was closed. Signals were not numbered to correspond with the levers - each station had its own code and numbers.

The upper signal is a three-aspect searchlight, but below is an additional capable of showing red (as shown here) or a miniature yellow aspect to admit trains into an occupied section. This unusual feature allowed trains to "buffer up" at times of congestion (and even couple up if one had broken down), or pass over a defective track circuit, without any need to involve the signalman. This was particularly useful as most boxes on the line were only opened when needed.

Between the two signal heads is a "Track Dead" indicator, showing that the live rails ahead have been de-energised (on this occasion for engineering work) to warn drivers of electric trains not to proceed.

The large white diamond with letter T indicates there is a telephone provided at this signal (they were not provided at all signals) which may seem pointless as the signal box is so close, but this would be switched through to the next box when this one was closed.

At the foot of the post are two Midland Railway shunt signals leading into the "Lie-By" reversing sidings. These were rare outside Midland territory, and their presence can only be put down to the fact the box was erected in the year the LMS was formed.


LNW shunt signal at Harrow No2Standing in the box doorway in the view above is your scribe.

The two signals controlling the exit from the Lie-By sidings were the more expected LNWR miniature arm type, and were probably the last of the kind in use on British Railways.

Behind the signal, the rodding interlocks with the position of the points to ensure the points are fully set before the signal can be cleared. This is called "Point Detection".


Inside Harrow No2 box Stepping inside the box, we find an LNWR Tappet frame of twenty levers. These can be visually distinguished from the Tumbler type (seen at Widnes No7) by the longer stirrup handle, provided to give extra leverage as this worked the locking mechanism on the tappet frames.

This picture was taken on a different day, when the box was closed - the last signalman on duty has placed a reminder "loop" on some of the signal levers.

The furthest lever, No20, is painted green and is the "closing lever" which switches the signal telephones through to the adjacent boxes.


Another view inside Harrow No2The Up Home and Starting levers were 2 and 3. Lever 1 was the distant signal in semaphore days, although this wasn't here for much of the box's lifetime. Notice, though, that the description plate marked "DISTANT" is still there, although thoughtfully painted white by the painters.

Notice also that the levers have not been cut short to indicate power operation, as would have been done if the signalling had been installed or changed more recently.

For many years of its life, Harrow No2 was only manned as required by Porter-Signalmen that normally carried out ticket collecting duties. By the 1970's, there were no passenger booked trains to reverse here, but the box opened once a day at lunchtime to shunt an Up mail train to the Down platform. This move had been carried out every weekday since the 1952 Harrow train crash which destroyed the lifts on the Up platform.

In the 1980's, a regular Bakerloo Line service terminated here, and the box became staffed on two shifts in its final years.


Lever description plates at Harrow No2Harrow No2 boasted a full set of original LNWR-type cast iron lever badges and description plates.


The signalman's diagram at Harrow No2The signalman's plan in the box was a handpainted LMS illuminated diagram, with delightfully brushed flowing curves. Red lights indicate the presence of trains.

There were large areas of line where the track circuits were not indicated in any signalbox, as the permissive operation negated the need for the signalman to know where every train was.

Please click on the image to view an enlarged image of the diagram. Regrettably, though, all of the detail is not visible.

If you look closely at the diagram, the name shows signs of being altered at some time. Under the paint, the outline of the words NEW LINE were visible, suggesting the box carried this name at one time. This perhaps explains the presence of an BR-era enamelled box nameboard, although no record exists to show any change of name to the box over the years. No1 box was once, of course, just opposite and controlled the Fast and Slow Lines.

Harrow No2 box closed in December 1988 and the one surviving reversing siding was transferred to the controlof the panel box at Willesden Suburban.




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All photographs copyright © John Hinson unless otherwise stated