Train Order Signals

The purpose of a train order signal is to stop trains at a telegraph station for the delivery of orders from the dispatcher. The train order system is an American invention. It was tried briefly in England, but fell out of use there as the manual block system became general. Its principle is the assignment of a single official, the dispatcher, who is in control of trains on a division, a defined length of track, by means of telegraphic communication with operators along the line, who pass on his orders to trainmen. Train order signals were used only in America, and were an essential part of the system of operation by train orders. They were not like the station signals used in Europe. It is curious that they resembled the first railway semaphores ever used, in 1842, by having two arms for opposite directions on the same mast.

This system appeared as a supplement to the time table when telegraphic communication was finally available for railway purposes, about 1855. Before that time, telegraph lines were under the control of telegraph companies, who carried on bitter patent wars with each other. To build a line, you had to pay for the patent rights. These lines were operated as a public message system, closed during the night, and manned by telegraph employees. They were, in general, unreliable and could fail unexpectedly. Messages were corrupted in transit, especially when manually relayed from circuit to circuit. It is no wonder that the telegraph was of little use in railway operation at this time. American railways, almost entirely single track, were run by time table. This method had been developed over about twenty years, and worked fairly well so long as railways were short and trains were slow.

However, it was never easy to handle delayed trains, especially important ones for which other trains had to wait, or to run extra trains to handle traffic emergencies. As soon as the telegraph appeared, which in the United States was after 1844, it was recognized as an answer to these problems. The famous stories about Charles Minot on the Erie are evidence of this. Minot had seen that the Erie acquired a bankrupt telegraph line along the railway around 1850, and took advantage of it to begin using telegraphic messages to move trains. When the Pennsylvania entered Pittsburgh in 1854, it brought a railway-owned telegraph line with it, and pioneered the dispatcher system. The deal with the telegraph company was that they could use your right-of-way in return for giving you a dedicated line which could be used 24 hours a day and properly maintained. A great deal of development was necessary before the message became the train order, but the train order was in general use by 1874. The system was perfected in the Standard Code of Operating Rules adopted in 1889 by the Standard Time Convention, which later became the American Railway Association.

The difference between a train order and an ordinary message is that the train order is prepared, transmitted, and delivered according to very strict prescriptions. A train order must be repeated to ensure accuracy, delivered to those who are to execute it, and expressed in the same words to all involved. These seem simple requirements, but actually cover a great deal of ground and were often violated in earlier systems. Originally, a train order had to be signed by the conductor and engineman in the presence of the operator, and the signatures transmitted back to the dispatcher, before the order was considered to have been properly delivered. Experience showed that this was far too restrictive. Once an order had been properly transmitted and repeated, there was very little chance that it would not be delivered.

For many years, there were two kinds of orders, the "31" order on yellow tissue that had to be signed like the original train order, and the "19" order on green tissue that could be delivered without taking a signature. The conductor could sign for a "31" order and deliver it to his engineman in most cases, so the engineman would not have to leave his engine and go to the office, which was inconvenient and time-consuming. The "19" order was handed up to the front and rear end of a train without a stop.

Although the "31" order was considered more reliable, in fact it was no more reliable than the "19". The "19" order was handed up to the front and rear end of a train without a stop. The time saved by this method of delivery cannot be well appreciated by those not familiar with train operation. Instead of wasting a good quarter to half an hour, delivery was instantaneous. The purpose of the tissue order form was so that manifold copies could be made with the newly-developed carbon paper and a stylus, with a stiff tin as a backing inserted into the pad. The carbon paper has carbon on both sides, to make the copy darker. Orders can also be read by transmitted light when held up to the open firebox door.

Although the "31" order was considered more dependable, in fact it was no more reliable than the "19" order. If a "19" order would fail, then so would a "31" order under the same conditions. Many companies eventually abandoned the "31" order, retaining only an undifferentiated "Train Order" that could be signed in those very rare cases in which it seemed desirable (as when an order was delivered by a messenger, and not in the usual way).

The train order signal was largely responsible for the reliable delivery of orders. Each operator would report the time each train passed his station to the dispatcher (the "OS" report), so the dispatcher would know the location of all trains at all times. When he issued an order, he would send the station calls on the dispatcher's wire, and then, say, "19 east". Each operator addressed would then put out a stop signal, and reply with his station call and "SD east". The dispatcher was then certain that the trains involved would be stopped at the points where they were to receive their orders.

This done, he transmitted the order, underlining each word that he had written in his order book. Then the operators addressed repeated the order. As each did so, he underlined each word again, and if all was correct, gave them "Complete", which they wrote on the order in the place provided, with the time. The operator knew to make three copies, one each for the conductor and engineman, and one for the file, unless the dispatcher had told him to make more (or fewer). Orders were addressed to the conductor and engineman of a train (C&E), or to an operator (Opr).

It was very important to get the order to the correct train. The operator could not assume an approaching train's identity from how it looked, not even from the engine number, but had to know who it was. To do this, he kept the stop signal displayed, and gave to each train that arrived a clearance card for conductor and engineman, addressed to the train he presumed it was. This allowed every train to proceed, until the one that was to receive the orders arrived. It was necessary that the conductor and engineman compare the train identified on the card with his actual identity. The train to which the orders were addressed got the orders, not a clearance card. The role of the clearance card was later greatly expanded, and it became a very useful aid to safety.

The reader may agree after a little consideration that the delivery of an order was practically certain, whether "31" or "19" or just a generic order. The only way it could fail was if the train was beyond the train order signal, or the train ignored it, or the operator forgot the order or did not display the signal. There is an article on this website that deals with errors in train order operation, and several cases of nondelivery are analyzed there. These examples only confirm how rare this failure was.

Train orders came into use more than twenty years before semaphore signals became at all common in the United States, so the first train order signals were flags and lanterns displayed in a designated place on the station platform. On the Chicago, Burlington and Quincy, the train order signal in 1883 was a green flag or lamp. These signals usually applied to both directions. A train in the opposite direction to the train addressed in an order was allowed to pass with a hand signal with no further formality. Some later train order signals also applied to trains in both directions, and were handled the same way.

When semaphore signals became common, after about 1880, they were adopted as train order signals. Usually, arms for both directions were mounted on the same post, with a single lamp for night aspects in both directions. A train was governed by the arm pointing to the right. In the case of multiple tracks, the signal applied to all tracks and to trains moving against the current of traffic. The signal mast was conveniently placed on the station platform in front of the telegraph office, from which the operator had a view in both directions along the track. If visibility was restricted, the mast was sometimes placed on the far side of the track. These signals became by far the most common semaphore signals in the United States, placed in front of every station with a telegraph office. They were easy to sight, and every train approached under control ready to obey their indications.

One way to operate the signals was described above. The signals were held at Proceed unless an order was received for a train, when it was changed to Stop. A better practice was to keep both arms at Stop while an operator was on duty, only fastening them at Proceed when the office was closed. If there were no train orders for trains in the direction of an approaching train, the signal was cleared as soon as it was in view of the train. This showed the train crew that the operator was alive and alert. If there were orders, it was handled as described above. Sometimes a signal had to be held at clear; if the lever was released, the arm went to horizontal by gravity. A pin was availble to fix the signal at Clear when the operator was off duty, however. It would have been easy to repeat the position of the train order signal by lights on the operator's desk (operators could often not see the signal arms without going outside). Although this was probably done, I do not know of any examples.

On the Illinois Central in 1891, an engineman approaching a train order signal at Stop called for signals (four short sounds) when he was 200 yards away. When the signal changed to Clear, he acknowledged it by two short sounds, the usual acknowledgement for any hand signal. If it did not change, he gave one short sound (brakes) and stopped to receive orders. Trains had to stop short of a train order signal at Stop, and were not allowed to pass a station where the signal had not been seen to change. These whistle signals went out of use in the 20th century where they had previously been used. Changing the signal in sight of the train continued, where it was the practice.

If a train approached a train order signal at Stop, and the operator was not seen on the station platform ready to hand up orders, then the train had to stop and the conductor had to go to the office. On the other hand, if the operator was seen on the platform with his hoops or forks to hand up orders, and had a green lamp with him (at that time, green meant Caution), it was clear that he was going to hand up "19" orders or a clearance card, or perhaps just a message, and the train would slow to 30 mph or less to facilitate delivery. Later, a yellow lamp was used instead of the green lamp, often hung on a hook on the signal post. In bad weather, or when the train orders restricted a train abruptly at the station, the train order signal was backed up with torpedoes, and the train was actively flagged by the operator. The fact that the train order signal was accompanied by the live operator helped to see that it was observed properly by enginmen, unlike an isolated signal in the country.

An order hoop was a thin cane bent in a circle at one end and tied. The orders were tied to the hoop so they could easily be slipped off. The operator held up the hoop by the straight end, and the trainman thrust his arm through it. After removing the orders, he threw the hoop aside. An order fork was a Y-shaped wooden piece. The operator tied the orders to a loop of string that was held by spring clips on the fork. The operator held up the fork by its handle, and the trainman thrust his arm through the loop of string, pulling it off the fork. Hoops or forks could be held at the proper height by inserting them in holes or clips of a post. This post could also hold the lantern, and the operator did not have to be present. Orders were handed up on the side where the operator was standing, generally the station side if no specific instructions were issued. The fireman received the orders on the engine, crouching in the gangway in front of the tender. A brakeman received the orders on the rear end, standing on the caboose steps. By night, these men should carry a white light to show their positions. A helper engineman also had to receive orders, as did a pilot, if one was assigned when the engineman was unacquainted with the route, as with a detoured train.

Some companies thought it best for the train order signal to indicate clearly whether a stop was required, or if orders were to be handed up without stopping. This required a three-aspect signal. Some early signals had been developed for manual block, and displayed not only Stop and Proceed, but also Permissive. These were pressed into use, with the Permissive aspect used for "19" orders. Lower quadrant three-aspect signals had also been designed in the 1890's for the same use, while three-aspect upper quadrant signals appeared around 1906. By this time, green for clear was becoming standard, and train order signals were modified to show red and green instead of red and white. Yellow was then used for the "19" order position. If a "19" order restricted a train at the station, the train order signal was maintained at Stop, and the train had to stop.

Where a train was required to report for orders, as at initial stations, a train order signal was not necessary, and one was not provided. For a train to start, it had to have a train order or a clearance card to give it life, unless specially provided in the time table. At the ends of some branches, where no operator was on duty when a train was scheduled to leave, the train was permitted to leave without any paper by special instructions, but this was very unusual. Extra trains, of course, and sections, normally required train orders. On double track, such trains could sometimes be started with a clearance card only. This was safe, and saved the dispatcher a lot of work.

Classic train order signals are illustrated at the right. The company from which the example was taken is given, as is the date of the rule book containing the aspect. The names of the aspects are as shown in the rule books. The Michigan Central signal shows the use of a round end to the arm to indicate a train order signal. The MKT and B&M signals were the same pattern, but with a square-ended blade. The Midland Valley signal uses a three-position upper quadrant arm, but the 45° aspect is not used. This signal is unusual in requiring two signal lamps. The Southern Pacific signal is a widely-used type. It has a square-ended red arm painted white on the back. The middle roundel is not used, only those for horizontal and 60° depression. However, the middle roundel was yellow, instead of red on the "continuous light" principle to guard against partial operation. This intermediate position was not distinctive enough to be used as an aspect. The Pennsylvania relied on the block signal to stop trains. Train orders were indicated by a yellow flag by day, and a yellow lamp by night, at a fixed location. A flashing "O" light was also used, on the signal concerned.

Where block or interlocking signals were used to stop trains for orders, a red flag or lamp sometimes meant stop for "31" orders, and a yellow flag or lamp meant slow for "19" orders. These signals were usually acknowledged by two sounds on the whistle, after which the block or interlocking signal would be changed to its usual aspect.

Simple rotating target train order signals are shown at the lower right above, and in the figure at the left. The Nunn signal was of this type. This signal applies to both directions, and is displayed at Stop when train orders for either direction are held. The means of returning the signal to Stop by gravity is shown, by a pin in a helical slot. Not all target signals used this method. Bevel gears were frequently employed to rotate the target. The signals shown in the figure could be seen in Lincoln, NE in the 1970's. The CNW line to Lander, WY used these signals, as at Douglas and Riverton.

The Santa Fe signal was adapted from a three-aspect manual block signal introduced around 1898. Only the two aspects shown are used in a train order signal. The third aspect, with the blade inclined upwards and a yellow light, was the manual block permissive aspect, as well as the restricting aspect at interlockings, in place of a second arm. It was thought that this aspect was already worked to excess and should not take on a third duty. The yellow roundel was often retained in later days, though not used. The blades were basically black, but could be white, or even striped, if this contrasted better with the background. The Mozier three-position block signal, or US&S Style D, used on the Erie west of Salamanca was quite similar, except that the spectacle was on the bottom, not the top. The counterweight was disengaged when the arm was raised, so that the signal returned to Stop from either less restrictive position. Whenever the signal was not displaying Stop, a contactor closed the operator's key circuit, so he could not communicate. At the time of their introduction, these signals were known as "three-phase".

At the left, train order signals from the Southern Railway are illustrated. Many other companies used similar signals. Both two-position lower quadrant and three-position upper quadrant signals are shown. On the Southern, train order signals were kept at Stop when an operator was on duty, outside of automatic block territory. It was changed to Approach or Proceed in view of the approaching engineman. In this connection, Approach meant to pass the station at reduced speed for the delivery of a clearance card. If a "19" order did not restrict the train at that station, the operator could place the signal at Approach before the train was seen. At stations where there was no train order signal, a red flag or red lamp was used instead. On double track, or when automatic block signals were in operation, the signals were maintained at Proceed except when orders were held for delivery.

The Rock Island and Frisco train order signal arms are examples of yellow and black blades. The end of the Rock Island blades is round, but the black stripe is straight. The NP used a similar signal, but with a square-ended red blade with a white stripe. A Frisco train order signal more often used a single lamp at the top of the post, but this example, that was at Perry, Oklahoma in 1950, has the two arms at different levels. The NP target signal was located at Fromberg, Montana, where the CB&Q from Laurel diverged onto its own tracks. This junction, incidentally, was over a diverging turnout with a 15 mph restriction. The little-used branch to Bridger, 7 miles further on, went straight ahead.

Color-light signals were also used as train order signals. Because these are not as distinctive as semaphore signals, it was necessary to distinguish them in some way. An easy way was to use a sign "TO" on the mast. The Elgin, Joliet and Eastern did this, and also considered a horizontal color-light signal distinctive enough. The "TO" sign was reflectorized white letters on a black background. The signal was often three smaller light units without an overall background. These signals, and the aspect names used by the EJ&E, are shown at the left. Many color-light train order signals had no such identification, usually only just two arms back to back on the same mast in the style of semaphores. Where there were no automatic block signals or interlocking signals, a two-aspect signal with red and green lights was satisfactory. A good idea was to make train order aspects blink, if they could not be confused with other blinking signal lights. This was done, for example, by the Burlington Northern.

If there were interlocking signals, train orders were usually indicated by a yellow flag or lamp in a window of the tower, and trains were stopped with the interlocking signal. When an engineman saw the yellow flag, he acknowledged the fact with two blasts on his whistle. If a "19" order was to be delivered, the signalman then cleared the interlocking signal, and the train proceeded without stopping. If the signal was not cleared, the train had to stop. Recall that fixed signals are not acknowledged by the whistle. Some interlocking towers had regular train order signals, however.

After 1900, manual block expanded greatly from its previous use on a few trunk lines, driven by public and regulatory pressure. If the train order signal was pressed into duty as a block signal, this could be done at practically no expense. Automatic block signals were much more expensive, but they did save labor costs. However, where the operators were required anyway for train orders or to operate and interlocking, there would be no extra expense for manual block. This double use introduced an element of danger, for example as when a signal might inadvertently be cleared as a block signal when there were still orders to be delivered. The train order signal had always been used to space trains by time anyway, which was not necessary with the block system. Another problem was that trains were not usually required to stop short of a train order signal, and train order signals were not located with reference to stopping points. This problem of clearance in advance of the block signal was not clearly solved. Nothing was done about this problem in most cases, since the block system was supplementary to time table and train orders, and proper flagging was still required when stopped by a block signal. In general, a train finding a train order signal at Stop only has to stop short of the switch used by an opposing train in clearing the main line. It must not, however, leave the station withough a clearance card.

The New York, Chicago and St. Louis (Nickel Plate) used a three-position upper quadrant semaphore in a unique way. These were both train order signals and block signals, and the Stop aspects were distinct for the two purposes. Train-order Stop was the 45° position, while horizontal was Block Occupied. This figure also illustrates the old signal colors.

The clearance card, from its intial function of clearing a train past a train order signal at stop when orders were held for delivery, gradually expanded its scope. The first change was always to deliver a clearance card with orders, and to specify the number of orders accompanying it. Then the order numbers were specified, so the clearance card became an index to the orders received. Some operators had already started doing this before it was required. Finally, the dispatcher was required to "OK" the clearance card. He could check that the proper orders were being delivered, and that none was forgotten. Also, the clearance card could now be used to authorize a train to assume its schedule.

Other forms, similar to the clearance card, were often used. On the CB&Q, form A was the usual clearance card supplied with orders; form B was a clearance card for use with inoperative signals or failure of communications; form C was a "permissive" card authorizing trains (freight trains) to enter an occupied block and proceed at restricted speed. The Kansas City Southern issued a "terminal clearance" that also listed overdue trains. This was not a particularly good idea if it would lead to less vigilance in checking the train register. The wording implied that the conductor had to check the train register anyway, so this form would not save any time, but would simply be a double check.

If an operator held no order restricting a train in the same direction at his station, the Southern Pacific allowed him to "wink" the train order signal as soon as the train appeared to indicate that such orders or a clearance card were to be handed up without stopping. The "wink" consisted of lowering the arm and raising it again quickly twice. Outside of block signal territory, the dispatcher had to authorize this.

Train order signals were not used to govern routes; that is, as interlocking signals. They were used only to: (1) stop trains for orders; (2) space trains according to Rule 91; and (3) as manual block signals. They were manually operated by the signalman nearby.

The signal collection of Brian Maiher contains many interesting examples of train-order signals. The sketches accompanying this paragraph were drawn from photographs taken by John Ingham. The Norfolk and Western and Reading signals show an unusual arm shape, with notches at the end. The N&W arm is the Mozier patent 3-position arm, intended as a manual block signal and used on the Erie. On the N&W, it may have been a 3-position train order signal, with Stop, 19-Order and Clear aspects. If used as both a manual block and train-order signal, it would be put at Stop if orders were to be delivered; the state of the block would be stated on the Clearance Card. The 45° positions indicate that there are no orders. The Mozier signal does not use the weak vertical arm aspect.

The Reading signal may have been used as a 3-position lower quadrant signal. The 19-Order aspect would be about 30° below horizontal, the Clear aspect at least 60° below zero. Most companies avoided using two lower-quadrant inclined aspects because of the danger of confusing them.

The more familiar round-end blade is shown on the two arms illustrated on the left. The upper arm is the very frequently used 3-position upper quadrant signal. One lamp with lenses on opposite sides can illuminate two arms, one for each direction. The Clear aspect is vertical, easily distinguished from the inclined and horizontal aspects. Note that this arm does not need a heavy spectacle, since its weight will naturally return it to Stop if the connection should break. The lower arm is stated to be from the NYNH&H, which used round-end arms for interlocking signals. This arm was not used as a 3-position arm because of the possiblity of confusing the inclined aspects. The 1956 NYNH&H Rule Book shows only two-position, lower-quadrant train order signals with square-end arms.

Square-end train-order blades are shown at the right. Both signals are 2-position lower quadrant. The Clear aspect of the W&LE signal seems rather close to vertical, while the Seaboard signal depresses to only about 45°. In either case, the inclined position is easily distinguished from an accurate horizontal postion, which is set by a stop on the counterweighted arm. In either signal, the lamp is at the top of the post and serves both directions.

Two common 3-position lower quadrant train order signals are shown at the left. In both cases, the Clear aspect shows a vertical arm. This was the pattern of the first 3-position signals developed on the PFtW&C jsut before 1900. Though rarely seen as block or interlocking signals, they were later often used as train-order signals. The lowest part of the B&M arm is a counterweight with a hole in it, not an extra roundel. The Monon arm has an extra roundel, which allowed some flexibility in placement of the lamp. In the arm shown, the lamp was behind the left-hand red roundel (though the right-hand one was still there). Again, a vertical blade is the Clear aspect. If the right-hand red roundel is used for stop, the colors in the others must be modified accordingly. The bottom of the Monon arm is a thick counterweight.

The Grand Trunk train-order signal shown at the right is a two-position upper quadrant arm. The pivot is placed so that Clear corresponds to a vertical arm. The weight of the arm causes it to fall to Stop in case the connections fail. The stop adjustment is at the lowest part of the arm. The lamp is placed behind the red roundel in this postion.


Where the Standard Code was in force, Rule 221 in any rule book governed the use of the train order signal.

Railroad Gazette, 6 April 1900, pp. 222-223. AT&SF and Erie 3-position signals.

Railway Age, 4 July 1902, pp. 24-25. "Position" and "Continuous Light" Signals.

B. Solomon, Railroad Signaling (St. Paul, MN: MBI Publishing, 2003) has several good photos of train order signals, and shows handing up of orders.

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Composed by J. B. Calvert
Created 8 August 2004
Last revised 10 August 2004