CHAPTER XIX.

COLOUR-BLINDNESS IN RAILWAY EMPLOYÉS.

It is obvious from what I have already said, that persons belonging to classes of the colour-blind which it would be necessary to exclude from employment as sailors, would be equally dangerous if employed as engine-drivers. In addition to this, colours are used on railways which are not employed at sea, such as purple and blue.

In the early part of August, 1889, I issued a circular to the managers of the principal English railway companies requesting for information concerning the colours of the lights used on their railways. Most gave the information desired. My purpose in making the investigation was to find out at what class I should draw the line in excluding persons from being employed as engine-drivers.

The Midland; and London, Tilbury, and Southend Railway Companies use red for "danger," green for "caution," and white for "all right." The London and North Western use a red light for a "danger" signal, and a white light as an "all right" signal for intermediate block cabins and unimportant stations, and the green light as a "caution" signal for junctions and important stations. The following use red for "danger," and green for "all right”—Great Northern; Metropolitan; Eastern and Midlands; Metropolitan District; London, Brighton, and South

Coast; and East London. The Great Western Railway Company use red for "danger," and white for "all right."

The London, Tilbury, and Southend; and Eastern and Midlands Railway Companies, in common with many others, use a purple ground disc as a stop-signal for siding and shunting purposes only. The Great Northern Railway Company uses a tint of yellow-green instead of the bluegreen, which is used by most companies. This they do on account of the fact that the light is reduced to a much greater extent in passing through a blue-green than in passing through a yellow-green glass. A purple light, when exhibited on a fixed post on the "slow" or "additional" lines is the "all right" signal for these lines.

It will therefore be seen that the lights used by the different railway companies are by no means uniform in colour and method. Whilst a red light is the universal "danger" signal, green is the "all right" signal on some lines, white on others. Again, some companies use all three signals, green being used as a "caution" signal. The tint of green also varies; for whilst the majority of the railway companies use a blue-green, the Great Northern Railway Company uses a yellow-green light.

A purple light is used by many companies as a "stop" signal for siding and shunting purposes; whilst the Great Northern uses a purple light as an "all right" signal for the "slow" or "additional lines."

The London, Brighton, and South Coast Company uses red as a "danger" signal, and blue-green as an "all right signal throughout; the ground discs having similar lights to the semaphore signals.

As far as the signals go, the colours to be distinguished are, red, white (yellow), yellow-green, blue-green, and purple. A blue light is also used for the lamps of

trains, and therefore this colour must be added to the list of colours to be distinguished.

The remarks which I have made in the chapter on "Colour-blindness in the Navy," with regard to the coloured lights, are equally applicable to those on railways. Red and blue-green are the colours which are most easily distinguished from each other by normal-sighted persons. An ordinary red-green blind will distinguish a blue-green from a red light with greater ease than he will if the green be of a yellow tint. Unless the yellow-green glass be very carefully chosen, it may lead the normal-sighted into trouble. The reason why the Marine Department of the Board of Trade altered the hue of the green from a yellow to a blue-green was that the colour in a fog appeared very much like a dirty red.. Many yellow-green glasses are transparent to many of the red rays, and these rays, with their superior penetrating power, will, in a fog, very considerably influence the colour of the light.

There seems to me no reason why the three lights, red, green, and white, should not be sufficient for all ordinary purposes. It does not seem to me that a "caution signal is necessary, and that it would be better to have a positive “all right" signal, such as the green light. Then, if the glass of the red light were broken, there would be no danger of an accident occurring through it.

I do not think it is necessary to use a different coloured light for siding and shunting purposes. At any rate, a purple or blue light should never be used as an “all right” signal, because glasses of this colour are transparent to the red rays, and so the colour might easily be converted into red.

Having shown what colours it is necessary for the engine-driver to distinguish between, let us consider the

tests used by the different railway companies, and their efficiency for the purpose required. I am indebted for most of the information concerning these tests to the Railway Press. The editor of this paper issued a circular to the managers of the different railway companies, requesting for information concerning the methods employed in testing for colour-blindness. In the majority of instances a reply was sent, giving details of the tests used. The answers are published in full in the Railway Press, September and October, 1889, and are well worth perusal.

The North British Railway Company test with a board placed thirty feet distant, with seven coloured spots printed on it, viz., white, red, green, brown, blue, black, and yellow. The test is conducted personally by the locomotive superintendent. Every fireman, on being appointed, is tested for colour-vision, and again when he is appointed as a driver. No further tests are made unless some grounds arise for believing that a man's vision is impaired.

The Great Northern Railway Company test with skeins of coloured wool. The method is not described.

The Midland Railway Company test with a modification of Holmgren's wools. The examination is conducted by the company's clerks.

The North Eastern Railway Company test with skeins of coloured wool, and by such other tests as the company's surgeons think it desirable to make.

The London and North Western Railway Company test their men annually with a card on which four colours are printed, with a series of dots for testing the vision between each pair of colours. The upper pair of colours are red and green, the lower pair blue and yellow. The examination is made by the foreman of the different districts. If any of the men fail to pass, they are examined subsequently by the company's surgeon.

The London and South Western Railway Company test with coloured wools and lights as follows: "When examined with the lights, the men are tested in a dark room, and they have to name them correctly. With the wools, they have to pick out a certain number of skeins of the colours in varied shades, and name them correctly."

The South Eastern Railway Company test those applicants who do not intend to become engine-drivers, by requiring them to match colours from a collection of coloured objects or wools of various tints, and by "Snellen's Tests." Applicants for employment as enginedrivers enter the service as engine-cleaners, and, as a preliminary, a collection of coloured wools is placed before the candidate, and he is requested to pick out various colours as directed; and, unless he is able to distinguish the colours readily, is not considered eligible. In time an engine-cleaner is promoted to fireman, and, on this taking place, the colour-test is again applied, supplemented with hand-flags at various distances.

The London, Brighton, and South Coast Railway Company appear to test by Holmgren's method.

The London; Chatham, and Dover Railway Company test with coloured lights in the following manner: A tube, twenty feet long, is used; at the end of which is a revolving disc, containing a series of coloured glasses. The colours are confined to the primary ones. The examiner can revolve the disc to any colour he likes, and asks the candidate the name of the colour. The candidate is also tested with a distant signal at eighty yards, which is under the control of the examiner,

The North London Railway Company test by cards, with coloured stripes and spots respectively.

I can hardly conceive anything more unsatisfactory than most of the above-mentioned tests. The test, for