When did speedos for locos become the norm ?

Question

The SMITH'S speedometer used to be attached to the DJ class in New Zealand. Are these still in use worldwide, or no

??

Answer 1

Mechanically driven speed recorders were in place by the late 40s, early 50s on American railroads.  Speedometers were in use before that time, however, on steam engines.

The most common were the units made by BARCO.  As pointed out above, they did have a paper with a stylus that noted the locomotives speed.  They were driven by a direct connection to an axel on the locomotive.  On diesel electric engines, this was usually run off of the #2 axle.

The cable which drove the unit needed frequent maintenance in the form of lubrication. Lacking this, the internal "snake" in the drive line would break.

By the 60s electronic units were employed on most road locomotives.  The most common of these were the units mabe by SIS (Speed Information Systems), Prime and BARCO.  These had an alternator connected to the #2 axel and the speedometer head in the cab received these signals via wire.  These did not have recorder capability.

In the early 80s, event recorders were being applied to locomotives.  These were a simple device that utilized old 8 track type continuous tapes, that had the ability to record only 8 parameters, including speed, air pressures, etc.  But, when removing tapes for review, the reading device had to be calibrated to ensure an accurate reading, where speed is concerned.

On the outside of the locomotive wheels there is a groove, called the "witness groove."  The person removing the tape would measure from the outside of the tread of the wheel to the witness groove.  This number would then be fed into the device that read the information on the tape.

These units were usually made by SIS or Aeroquip.

Totday's on board event recorders are digital, of course, and have the ability to monitor nearly everything the engineer does, right down to the display of headlights.

As far as SMITHS recorders go, I know of none that were used in North America.

It is worth mentioning that, even when a speedometer is inoperative, the engineer is still responsible for the speed of the train.  There are mileposts (usually) that the engineer can use in conjunction with his watch, to time the distance between mileposts.  But, this is only a close approximation, as the mileposts are usually hung on a convienient telephone pole or such.

There are "measured mile" posts as well.  These are always free-standing, and the posts themselves are usually "zebra striped" in black and white.  These are there to check the accuracy of the speedometer.  On through trains, engineers confer at crew change points on the condition of the equipment, including the accuracy of the speedometer.

Answer 2

I am loco and have worn speedos for years.

Answer 3

All the locomotives I have worked on in the last 20 years or even more are part of an "event recorder" system, that can include air brake pressure, headlight, horn, bell, throttle setting, speed and distance, no voice recorders yet.

When I first started it was just a paper in a reel that had a stylus on it, if you were worried that the "tape" was not going to be your friend there were ways to override it, or just heave it out the window, not any more, it is all transmitted to the carrier via computer.

I have never seen a smith speedometer, actually here we call them speed recorders.

I remember the Barco ones, some models had a vertical rod next to the stylus you could slip an air hose gasket over and it would stop the needle from going up above whereever you set it at. that was kind of handy on the slow branch lines.

I remember when i went ot work there speed recorders on some locos that RR had acquired in the 1940's but I am sure they go back a lot farther, I am only going by my own personal experience.