Brief History of the Railroad

Before the railroad, travel often took weeks or months. Travel across the continent was dangerous, difficult and measured in months. Yet, within the span of 40 years, the Union Pacific - Central Pacific route was completed in 1869. This made it possible to complete the trip from the East Coast to the West Coast in just 7 days! With the completion of the Missouri River Bridge at Omaha in 1872, the trip could be made without ever leaving the steel rail.

In 1883, the current Standard Time Zones were established by the railroads to meet scheduling needs. By 1900, trains had exceeded 100 mph and were constructed of steel. They had the use of the air brakes automatic couplers. In addition, the Pullman sleeper car and the Harvey House restaurants made travel comfortable, especially for the privileged. The development of the telegraph made both the construction and operation of the railroads efficient while the rail right-of-way provided a route for the telegraph.

As the 20^th Century dawned, the "Old West" was gone forever - replaced by cities, industries and farms thanks to the railroad.

The Diesel Locomotive

The diesel locomotive began its service in the 1920's with small units in switching service. In the 1930's, passenger streamliners such as the Zephyrs began to be pulled by larger units. The CB&Q Zephyr (now BNSF) made the famous "sunrise to sunset" run from Denver to Chicago in that era. World Ware II slowed the pace of diesel applications, but by the 1960's the diesel was the only type of unit in regular service.

All locomotives in regular service today utilize an "electric transmission" as the drive. The diesel engine powers an electric generator and this in turn powers the rail wheels through an electric motor. A few experiments such as hydraulic drives were tried, but the efficiency and control features of the electric drive have prevailed. Early units had both direct current generators and motors, but the invention of robust solid-state rectifier devices made the use of the more durable alternators (AC generators) practical in the 1960's. The use of solid state controls began in the late 1960's. Further developments in the 1990's included the use of computers in the control mechanisms and the use of the more durable AC induction motors to drive the rail wheels.

The AC motor equipped units are more expensive (large locomotives have a price tag in the millions of dollars!), but are especially useful for heavy loads and steep grades. DC motor units are still being used for less rugged conditions.

The modern large locomotive is really a computer controlled electric utility on wheels.

Many Mid-Western towns owe their existence to the building of a railroad. Hooper, Nebraska is an example. These towns were laid out with a main street at right angles to the railroad. At the intersection of these was the depot, which was the site of activity for everything and everybody that arrived at or left the town. Immediately beyond the depot was the merchandising establishment which depended upon the depot as their connection with the railroad. Beyond this was the homes of the more affluent residents who wanted the greatest distance between them and the noise, dirt, and the often "unsavory characters" associated with the railroad.

However, those residents who were of a lower economic status were unable to afford the isolation of the affluent and were forced to live in the only other place available - across the railroad from the rest of the town. Hence the rise of the expression "Born on the Wrong Side of the Tracks". This phrase came to be applied to those of a more humble and disadvantaged background.

Towns which existed before the railroad may show a different configuration, with perhaps the main street in parallel with the tracks. It is an interesting activity as one travels to try to identify the "T" Towns and imagine what the railroad meant to them.

The Automatic Car Coupler

The automatic car coupler, along with the air brake, has made modern rail operations possible. After the development of locomotives around 1830, it became necessary to have a device to couple them and rail cars together. The first development was the "link and pin" device. Each rail car was equipped with a metal drawbar protruding from the car frame end. The outermost end of this bar had a horizontal slot which was intercepted with a vertical hole. When two railcars were to be coupled, an elongated metal ring (the link resembling a chain link) was inserted in the drawer slot of one car and secured by a metal pin through the vertical hole. As the other car approached, a person went between the cars and held the link so that it entered the horizontal slot of the approaching unit exactly at the right time when a pin would in turn be dropped to secure the link in the coupled car. This was a dangerous operation, leading to loss of life and loss of fingers and hands of the workers. In the days of unorganized, cheap and plentiful labor, this was probably not as great a concern as was the fact that the device was weak as the trains grew in size and it took time.

Many worked on a solution, but the ultimate one can be attributed to Eli Janney, a Civil War veteran and store clerk in Atlanta. He received a patent in 1873 on his unit. The working idea of his unit can be envisioned by forming one's hands into fists, holding knuckles of the fists together, rotating one fist 180 degrees, slighting opening the fingers, hooking the fingers together and then reclosing the fists.

In the actual coupler, the movable part (the knuckle) is locked into place by a pin which will fall into place by gravity when coupling (hence automatic) and can be safely lifted to uncouple by a "pin lifter" rod which extends to the side of the car. If the coupling of the cars is gentle, the pin can be heard to drop (hence the expression "so quiet you can hear a pin drop"). Although the coupler is very strong, the knuckles can be broken with poor train handling.

Railroad acceptance was not immediate, but was finalized by the federal Railroad Safety Appliance Act of 1893. The construction has been standardized so all couplers will connect will all others in use. It has been adopted many places world-wide, but some countries (Europe and some former colonies) use a modification of the link and pit yet today. Buffers and a turn-buckle arrangement are then also used.

The Air Brake

Once locomotives began to move trains in the 1830's, it immediately became obvious that there was a need to stop them. So rail cars were equipped with manual brake mechanisms operated approximately by "brakemen". When the train was to be stopped, the engineer gave whistle signals and the brakeman walked on top of the cars using handwheels to apply breaks.

The dangers of this procedure were great and the process was ineffective as trains grew longer and faster. The ineffectiveness, rather than loss of life and injury, was no doubt a greater motivation for improvement in the view of the classic railroad baron owners.

The idea of using the power of compressed air, which could be obtained from a pump on the locomotive, came into being. The engineer could then quickly control the brakes on the entire train without brakemen.

Early applications provided air directly to the train brakes for stopping. However, if the air line should separate, all braking would be lost.

It remained for a prolific inventor, George Westinghouse, to devise a process, now still in use, to overcome the separation problem. In this process, compressed air is piped through and stored in tanks on each car before the train leaves and is replenished as needed as the train travels. A clever valve on each car monitors the pressure on the train air line. To apply brakes, the pressure is reduced in the train line by the engineer and the stored air is used to apply the brakes. If the pressure reduction is very sudden, as in a separation, an emergency application occurs and the train is stopped in the shortest possible distance. For a long, heavy train, even this distance can be a half-mile.

Although the loss of braking if a separation occurs is not a problem in this scheme, the possibility of using up the stored air by poor braking techniques exists and does happen, causing a "runaway" train. The stored air cannot be built up again during brake application. Hence, the engineer must use skill when descending steep, long grades.

In 1869, at the age of 22, Westinghouse organized the Westinghouse Air Brake Company which would come to be later known as WABCO. One of his first railroad "demos" involved an emergency stop due to a carriage on a crossing. Official railroad passengers were jostled, but the sale was completed!

Side Note: Westinghouse (1846-1914) had 361 patents to his credit covering many areas - including a-c electricity.

The air brake, using stored compressed air, was invented by George Westinghouse in the 1860's and was in common use not very long after. A system of piping connecting the locomotive, which is the source of the compressed air, is used to store air in reservoirs under each railcar. The brakes are applied when the same air line has a reduction in pressure. A valve on each car senses this as a signal to apply the stored air to cylinders which activate the wheel brakes. When braking is finished, the air line is then used to recharge the stored air. Each railcar and locomotive has a handing flexible rubber hose at each end terminated with a metal coupling. These hoses couple the piping under each unit with the next unit and form a closed airline for the train. For almost all cars, these hoses must be manually coupled from unit to unit. The metal coupling devices - called "gladhands" - are made in such a way that they can be coupled easily, will stay coupled in usual service, but will pull apart with no damage under greater force. Should cars become uncoupled, the hoses will part, exhausting the airline pressure. This rapid reduction will cause all of the brakes on the air line to set tightly into an emergency application and is a "fail safe" feature.

If the air pressure is reduced in the line by a valve in the locomotive only, then all air would need to go through the airline to the locomotive. There would be a pressure reduction first at the part of the train just behind the locomotive, with braking, while the rear of the train would not be braking, causing the rear to run into the front. This could cause damage and derail a long train.

A modification soon was made to each car valve so that the line air would be exhausted more rapidly at each valve - all brakes apply soon and reduce the run-in effect. However, in spite of improvements, anyone who has been around a rail yard no doubt has heard a series of "bangs" between cars going from the front to rear of the train as the rear cars run into the ones ahead when stopping.

Freight car brakes, once starting to release, release completely. Passenger brakes are more complicated and can release partially.

Advancements In Railroads

Since the operation of the conventional freight train brakes depends upon a pressure reduction in the train brake pipe, any obstruction in the line preventing the reduction signal from propagating from the locomotive to the end of the train will result in partial braking - possibly leading to a severe accident.

When occupied cabooses traveled with trains, the crew could verify line pressure conditions and, if necessary, apply train brakes from there. When the caboose disappeared, it was replaced by a portable device inserted in the coupler at the last train care - the unit that provides the flashing red light on the end of the train. This unit originally provided a pressure reading by radio to the locomotive, but later improvements made it possible for the end unit to apply brakes by radio command from the locomotive. Thus preventing severe accidents.

The newest development in freight train braking is the electronic control of brake application. Although compressed air still provides the force to apply brakes, the application is controlled by electrical signals. All train brakes are applied at the same time, preventing possible damage and derailment. Since the air line pressure is not reduced, recharge of stored air in car reservoirs can continue even when brakes are applied - not possible under usual systems. Trains can be stopped in as little as 1/3 of the distance possible with conventional brakes. In addition to the safety benefits, trains can be run faster and closer together, expanding traffic.

The electronic system requires electrical power to each car, provided either by cable connection from the locomotive or by car generators. In addition, cable or wireless electrical control systems must be provided and so application has been limited. Different systems are not interoperable.

Cross Ties

The railroad right of way had three essential components: the steel rail upon which the railcar wheels ride, the cross ties upon which the rails rest and the grade which supports the ties.

Ties have three essential functions: maintaining gauge, surface and alignment. Gauge is the distance between the rails. This is undoubtedly the most critical function since the wheels will leave the rail at any speed if the distance exceeds limits, resulting in the railroad's worst fear - a derailment which can result in millions of dollars of loss. In the current Americas, the major standard is a distance of 4 fee, 8-1/2 inches. This distance can be traced back to Roman chariots in England. Narrow gauge lines, which typically operated in difficult terrain, had a distance of 3 feet. Gauge distance variations allowed may vary from two inches for low speed tracks to no more than a fraction of an inch on high speed lines.

Surface, which is the vertical dimension, may vary from several inches for low speed to no more than fractions of an inch on high speed. Alignment, the sideways dimension, has a similar allowable variation.

For the 170 year+ that railroads have operated in the United States, the principal tie material has been wood. Even today, according to the publication Railway Track and Structures (RT&S), 93-94% of ties installed are wood. Millions are produced yearly, with RT&S reporting an increase in production of 2 million in the past year! Properly treated, wood ties have a life span measured in decades. Wood ties will accommodate a variety of fasteners to attach the rail and enable the stone ballast to lock well into the tie to resist alignment changes. Wood ties are typically preserved with the use of creosote and therefore there are environmental concerns - particularly in the disposal of ties at the end of their life.

Concrete ties have recently been increasingly an alternative to wood. They obviously are not subject to decay and have cast-in-place points for rail attachment, assuring correct gauge. However, they do not lock to ballast as well as wood and will shatter under the impact of a wheel running off the rail.

Steel ties are useful where a minimum vertical dimension is critical. This would be essential, for example, if a bridge structure were marginally high enough to allow passage of "double-stack" intermodal container trains.

Other tie materials sometime used are "engineered wood", plastic and variations thereof. All the alternatives to wood typically have a higher initial cost, but this may be offset in the long-term by reduced replacement and maintenance requirements.

The classic rail to tie fastener for wood has been the steel spike. Fore the alternative materials, other fasteners of a "clip" type are generally necessary and require different attaching techniques.

Rails

Even in Medieval times and before, the efficiency of a solid wheel rolling on a solid surface guideway was apparent. An early application was with carts in mining operations. The advantage of this configuration was obvious for railroads, where heavy loads needed transportation over various forms of terrain.

Very early railroad rails were made by fastening strap iron bands on the top of wood stringers. Sometimes these bands would become loose and curl upward (called snakeheads), entering a passenger area with potential injury and were certain to cause apprehension among the riders.

Not too much time passed before the now common, all metal, inverted "T" trail cross-section was adopted.

Until the past several decades, rail was produced in short lengths - typically 39 feet (which could fit into the old 40 foot boxcar). These sections were then fastened together with bolts and short pieces of steel overlapping the ends of the rails - commonly called "joint bars" or a closely allied term. The train wheels running over these joints produced the traditional "clickety-clack" sound heard on train travel.

Rails are marked when manufactured with several identification marks. Most obvious are the manufacturer, the date of manufacture and the weight per yard. Rail weights have ranged from 65 lb or less to 141 lb per yard or more, with the light varieties in historic times and the heavy for modern main-line service. Rail is made of high grade steel and is very durable. Much of the FEVR rail is 90-100 lb and was manufactured in the 1920's. The oldest, lightest observed branch line rail in the area is 85 lb rail manufactured in 1906.

The heavy stresses produced by repeated passengers of steel wheels with a small contact area (about the size of a dime) eventually will wear even the best rail and can produce internal defects, causing failures. To provide early detection, sophisticated electrical / electronic test methods have been developed and contained in a special rail vehicle. These tests can be performed at high speed. The Sperry Company was one of the first to provide this service.

Sectional rail is joined by bolted joint bars. The joints in sectional rail, while producing the nostalgic sound, also produce weak spots in the rail system and a poor ride.

In the past several decades, the problems associated with segmented rail have been mitigated by using continuous welded rail (CWR). This eliminates most of the bolted joints. In this process, rail is shipped from the factory in lengths over 1/4 mile long on special flat cars equipped with racks to hold many lengths. At the installation site, the lengths are welded together using a thermal process (ignited thermite compound) or an electric process. Modern machines are able to replace ties and CWR in a continuous operation.

Although the problems of the bolted joint bars are eliminated, CWR has its own problems. A major one is the control of expansion and contraction with environmental temperature changes. The temperature at which the rail is lade down is called the neutral temperature. At any subsequent temperature above this, the rail steel wants to expand - below - it wants to contract. When segmented rail was used, the expansion-contraction could be accommodated in the joints. Normally, good ties and fasteners can control these tendencies, even in miles-long CWR. However, if there is an excessive amount of temperature induced stress or there is a fastener failure, the rail can suddenly leave its intended location. One of these occurrences is called a "sun kink". This is where the rail bows . In very hot weather, maintenance of way workers closely monitor the rail and train speeds may be reduced. In very cold weather, it is possible that stress produced by very low temperatures can produce a "pull-apart" with similar bad consequences.

Super Chargers and Turbo Chargers

The object of super chargers and turbo chargers is to compress and so increase the mass of air which is available for combustion in an engine and boost the power output. The supercharger is a positive displacement mechanically driven unit with intermeshing rotors while the turbocharger has an exhaust driven turbine wheel connected to a compressor wheel in the intake air ducting. While the supercharger increases the power output of an engine, it also absorbs some of that power, being mechanically driven. The turbocharger, driven by engine exhaust, uses waste heat, and therefore also increases efficiency while boosting power output.

Internal combustion engines are either two (stroke) cycle or four cycle. The four cycle unit has separate piston movements for compression, combustion, exhaust and intake of air. The two-stroke has only a combustion and a compression stroke. Some means of expelling exhaust and charging of air must be provided between the two strokes for forcing air through the cylinder. The EMD 567C diesel is a 12 cylinder two-stroke unit using superchargers and expel exhaust since there is no exhaust when starting. General Electric locomotives use four-stroke engines which do not need a device to force air into the engine when starting and therefore use turbochargers. Later EMD diesels also do use turbochargers successfully, however, by using a mechanical drive to spin the turbine for starting and low power settings and then disconnecting to use exhaust drive at higher power levels.

Because four-stroke engines can meet increasing emission pollution regulations more easily, most future engines will be four-stroke. EMD's new 6000 HP engine is a four stroke unit.

All bearings supporting a rotating mechanical part have some friction. In the case of one surface sliding over another with a lubricating film between, the friction or resistance to movement is much greater than in the rolling contact of roller (or ball) bearings - hence the name "friction" for the former.

For about the first 100 years of operating railroad equipment, axle bearings on rail equipment were of the "friction" type. The technology and manufacturing processes available precluded anything else. The axle rotated inside a "box". A space on the outside car truck assembly at the axle end contained a brass bushing and a lubricant supply. The box had a cover hinged at the top for inspection and the addition of lubricant. Initially, the lubricant was fed to the bearing with packed cotton waste. Later, spring loaded pads or wicks were used. If the lubrication failed, the bearing would heat quickly and produce the infamous "hot box" which would soon lead to axle failure and derailment.

In the days of caboose use, an alert crew could spot the smoking "hot box" and stop the train in time to avoid disaster.

When roller bearings became available, they rapidly supplanted the friction bearing since they require no periodic maintenance. Today they are used exclusively in modern railroad equipment. The roller bearing can easily be spotted, since they require no periodic maintenance. Today they are used exclusively in modern railroad equipment. The roller bearing can easily be spotted, since the rotating end can be seen and is not concealed in the "box". The friction bearing will only be found on historic tourist equipment.

The railroads employ the use of "hot box" detectors along trackside at intervals which can spot an overheated condition and notify the train crew. While still effective for heat from a dragging brake, they are not very effective for roller bearings which can fail rapidly and with a minimal amount of heat.

New detection systems have been developed which computer technology and the use microphones near the track. These systems can detect the sounds of roller bearing failure. Under development are bearings containing an internal defect sensor - but this is an expensive option for the hundreds of thousands of applications.

Railroad Signaling

Among the many signal systems used by railroads, the ones most important and visible to the public are the signals at grade crossings. If a highway vehicle and a train arrive at a grade crossing simultaneously, the vehicle always "loses". The Texas Department of Transportation has reported that such an incident happens every 90 minutes somewhere in the nation - sometimes with fatal results.

Passive signals - stop signs, the traditional "crossbucks" - all depend on the continuing attention of the highway driver. Active signals - lights, gate arms, bells, horns, "wig-wags" - (and years ago a flagman) demand the driver's attention. In addition, the active signals can be designed to adjust to the train's speed and direction.

The type of signal is determined by transportation laws which take into consideration location hazards, frequency and speeds of train traffic, and the frequency of highway traffic.

Nearly all signal systems rely on the electrical conductivity of the steel rails and the steel wheels connected by steel ales of the railroad vehicles. The wheel contact provides a "short-circuit" for any type of electrical signal applied to the rails. In the simplest system, a battery at a distance from the crossing (determined by the predominate train speeds) provides a small current to the rails which is sent to relays in a control enclosure at the crossing. These relays are activated by the current and keep the crossing signal off. When a train passes the battery, the current is shorted by the wheels, the relays de-energize, and the signal operates. More on this below.

Railroad Signaling at Grade Crossings

Passive Signals - stop signs, the traditional "crossbucks" - need only minimal maintenance and no power or control. But Active Signals - lights, gate arms, bells, horns, "wig-wags" all need a control system.

The method of controlling an active signal by having a battery supply current to the steel rails to keep the signal "off" was presented above. When the steel wheels of a train roll on the affected rails, the current is shorted and the signal operates.

This system typically consists of track "approaches" to the crossing on both sides and an "island" in the actual crossing area. When the train enters the approach rails, the signal operates. Circuits in the signal control detect the direction of the train through the crossing and when the train leaves the island area, the signals turn off. This prevents signal operation when the train is still departing in the approach entered from the island.

This system is simple and proven but has several disadvantages. The most important disadvantage is the fixed length of the approaches where the train activates the signal. A fast train will not give adequate warning time. A very slow or stopped train will operate the signals for an overly long time and motorists may become impatient and cross the tracks. This is an extremely dangerous situation for a multiple track crossing where a train may come by on another track.

Another disadvantage is the need for a remote current source - typically a battery - at the far ends of the approaches. These need maintenance and periodic replacement. Some solutions and other systems next issue.

In previous editions, the simple dc circuit with ac fixed length approaches was discussed. When the train enters the approach rails, a short circuit is produced, activating the crossing signal. This system does not allow for consistent warning times for trains at various speeds and has a battery at the beginning of the approach track that requires service.

Early attempts to accommodate the varying train speeds divided the approach into sections and relied upon electro-mechanical timers to adjust the warning times. However, the best solutions had to await the deployment of modern solid state electronics.

Solid-state electronics did lead to the replacement of the battery fairly early. In this system, an alternating current (ac) is supplied from the crossing control to one of the approach rails and a diode (one-way electric valve that can change ac to direct current (dc) is placed at the end of the approach - where the battery was. The diode changes the ac to dc, which returns via the other approach rail to the crossing control. The crossing control, when supplied by the dc, keeps the signal inactive.

When a train enters the approach and passes over the diode area, the diode no longer is effective since the train wheels produce a short between the rails and the current return is then ac - not dc. The lack of a dc at the crossing control causes the signal to operate.

While this system eliminated the maintenance intensive battery, it did not solve the fixed length / varying speed problem. More electronics was the answer - described in the next issue.

Side Note: FEVR has both the simple dc and the ac type crossing signal controls.

In previous editions, the simple dc circuit with ac fixed length approaches was discussed. When the train enters the crossing approach rails, a short circuit is produced, activating the crossing signal.

Although very reliable, these systems are not able to give a constant warning time before arrival of trains traveling at different speeds nor are they able to differentiate between a moving train or a stopped one. These situations can confuse the highway traveler and produce dangerous consequences.

The development of modern electronics has provided better systems. By using a principle similar to radar - but at a much lower frequency and confined to the rail - a signal is sent out from the crossing control and then - as in radar - the return "echo" is electronically compared to the original signal. This echo is changed by the shorting contact of the car wheels and their motion relative to the crossing. The comparison can indicate the direction of the train and its speed.

Thus, a constant warning time can be provided at the crossing for varying train speeds and the warning devices can be deactivated if the train is not moving, with resumption if it begins to move.

Those who have crossed tracks in a rail yard area may recall seeing a train stopped near the crossing with gates up. But when train motion begins, the gates and other warning devices will activate.

All system discussed in this series so far use the rails and wheel contact for activation. Next time - a system that does not use the rails.