Cab forward

DRG Baureihe 05 #05 003 in 1937

In steam locomotive design, a cab forward design will typically have the driver's compartment or cab placed forward of the boiler at the very front of the engine. On a coal-fired locomotive, the fireman's station remains on the footplate behind the firebox so as to be next to the tender. On an oil-fired locomotive, the fireman's station could be (and normally is) in the forward cab. This type of design was widely, though not commonly, used throughout Europe in the first half of the 20th century, often in conjunction with an enclosed body design and/or streamlining.

Visibility is greatly improved from the cab, and fumes from the chimney do not fill a forward cab in tunnels. However, the crew's prospects in the event of a collision are worse, and if the driver and fireman are in separate places it is difficult for them to communicate, just as in autotrains.

Germany: Deutsche Reichsbahn

In Germany, Borsig in Berlin built a one-off streamlined cab forward DRG Class 05 (serial number 05 003) 4-6-4 in 1937, with further development stopped by World War II. Fueled by pulverized coal and with the firebox at the forward end, this loco was built with huge driving wheels, 2300mm (90.55 in.) in diameter. The design speed was 175 km/h (109 mph), but its conventional layout sister 05 002 set a new world speed record for steam locomotives on 11 May 1936, after reaching 200.4 km/h (124.5 mph) on the Berlin–Hamburg line hauling a 197 t train, a record it lost two years later to the British LNER Class A4 4468 Mallard. In 1944, the streamlining was removed, but the 05 003 had by then already lost its cab forward layout.^[1] After the war, it pulled express trains in West Germany until 1958. It was scrapped in 1960.

Italy: Ferrovie dello Stato italiane

Italian cab forward locomotive, group 670

The state-owned Italian Ferrovie dello Stato had several cab forward locomotives, Class 670 and 671. These 4-6-0 engines had a three-axle tender, and were nicknamed "mucca" (cow). The engines (construction year 1902, top speed 110 km/h) were used to haul passenger trains on the Milan-Venice railway. A single Class 671 cab-forward was rebuilt as a Class 672 with a Franco-Crosti boiler in 1939.

United States

Forney design

(main article: Forney locomotive)

"Ariel", a Forney-type cab-forward locomotive: Front is to the left in this image (note location of headlight and cowcatcher)

Matthias N. Forney was issued a patent in the late 1860s for a new locomotive design.^[2] He had set out to improve the factor of adhesion by putting as much of the boiler's weight as possible on the driving wheels, omitting the pilot wheels from beneath the front of the boiler. Such a design would not have been stable at high speeds on the rather uneven tracks which were common at the time. Instead, he extended the locomotive frame behind the cab, placing a four-wheel truck beneath the water tank and coal bunker. In conventional Whyte notation, this resulted in a 0-4-4T locomotive, but when run in reverse it was effectively a 4-4-0T, with the track stability of that popular wheel arrangement, along with unobstructed visibility for the engineer, and improved dispersal of smoke and steam.^[3]

Forney's design proved ideal for the small, nimble locomotives for elevated and commuter railroads, and he licensed the patent design to many manufacturers. Large numbers of Forneys served in New York City, Boston, Chicago and elsewhere, but were superseded at the end of the nineteenth century by electrification and the development of subways.

Ariel and Puck were 2 ft (610 mm) gauge locomotives built to the Forney cab-forward design for the Billerica and Bedford Railroad in 1877 by Hinkley Locomotive Works of Boston.^[3]

Southern Pacific Railroad

Mallet compound locomotive, Southern Pacific Railroad

The best known example of the cab-forward design in the United States, the Southern Pacific Cab-Forward (also known to a lesser extent as "Cab-in-fronts" and "Cab-aheads") placed the cab at the front by the simple expedient of turning the entire locomotive, minus the tender, by 180 degrees. This arrangement was made possible by burning fuel oil instead of coal.

The cab forward design was widely used by the Southern Pacific Railroad.^[4] The design was able to deal with the peculiar problems of its routes. The 39 long tunnels and nearly 40 miles (64 km) of snow sheds of the Sierra Nevada could funnel dangerous exhaust fumes back into the crew compartment of a conventional locomotive. After a number of crews nearly asphyxiated, the locomotive was run in reverse. This meant that the tender was leading the train, which introduced new problems. The tender blocked the view ahead and put crewmen on the wrong sides of the cab for seeing signals. The tenders were not designed to be pushed at the lead of the train, which limited speeds. Southern Pacific commissioned Baldwin Locomotive Works to build a prototype cab-forward locomotive, then ordered more units before the prototype had even arrived.

All of the cab-forwards were oil-burning locomotives, which meant there was little trouble involved putting the tender at what would normally be the front of the locomotive. The oil and water tanks were pressurized so that both would flow normally even on uphill grades. Visibility from the cab was superb, such that one crewman could easily survey both sides of the track. There were concerns about what would happen to the crew in the event of a collision, and at least one fatal accident occurred on the Modoc Line in Herlong, California when a moving locomotive struck a flat car.^[5] Turning the normal locomotive arrangement around also placed the crew well ahead of the exhaust fumes, insulating them from that hazard. One problematic aspect of the design, however, was the routing of the oil lines; because the firebox was located ahead of the driving wheels (instead of behind them, the usual practice), oil leaks could cause the wheels to slip. A nuisance under most conditions, it resulted in at least one fatal accident. This occurred in 1941 when a cab-forward with leaking steam entered the tunnel at Santa Susana Pass, near Los Angeles. The tunnel was on a grade, and as the slow-moving train ascended the tunnel, water on the rails from a leaking cylinder cock caused the wheels to slip and spin. The train slipped backward and a coupler knuckle broke, separating the air line, causing an emergency brake application and stalling the train in a tunnel that was rapidly filling with exhaust fumes and steam. The oil dripping on the ties then ignited beneath the cab, killing the crew.^[6]

No other North American railroad ordered cab-forward locomotives, although some, like Western Pacific, did consider the type. Built to deal with difficult terrain, these locomotives became an easily recognizable symbol of the Southern Pacific. In total 256 such Mallet-type articulated locomotives, in three different wheel arrangements, were placed on SP's roster. One example of the type, Southern Pacific 4294, is kept at the California State Railroad Museum in Sacramento, California. It is a 4-8-8-2 locomotive and is the only one to escape being scrapped. It was also SP's last new steam locomotive, built in 1944.

North Pacific Coast locomotive 21, an early cab-forward experiment

A decade before SP's first cab forward, the North Pacific Coast Railroad, later part of the SP-owned Northwestern Pacific company, rebuilt an 1875 4-4-0 into an oil-fired cab-forward locomotive. This innovative engine was built by William (Bill) Thomas, the NPC master mechanic who was nationally known^[7] and holder of a number of patents. Thomas used the running gear and frame from NPC locomotive 5, the "Bodega", which had been wrecked in 1897, to build NPC 21. With the addition a new and unusual marine water tube boiler and an all-steel cab, installed in reverse order from standard engines, this unique creation earned Thomas a patent on the locomotive design. No. 21 entered service in 1900, but only lasted a few years. Although it reportedly steamed well, though with a sooty exhaust, the crews found it difficult to operate, and with fears of the possible results of a collision they dubbed it "The Freak". A negligent fireman allowed the water level to drop, damaging the boiler, and it was not repaired.^[8]

Prussia

Experimental Prussian T 16 (see in German) 2'C2' (4-6-4T) had control cabs at both ends.

UK: Southern Railway

Oliver Bulleid's ill-fated Leader is sometimes referred to as a cab-forward locomotive, but since it had a cab at each end like a typical modern diesel or electric locomotive, this designation is not entirely appropriate.

Discover more about Rail locomotives related topics

Steam locomotive

Steam locomotive

A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material to heat water in the locomotive's boiler to the point where it becomes gaseous and its volume increases 1,700 times. Functionally, it is a steam engine on wheels.

Cab (locomotive)

Cab (locomotive)

The cab, crew compartment or driver's compartment of a locomotive, or a self-propelled rail vehicle, is the part housing the train driver, fireman or secondman, and the controls necessary for the locomotive or self-propelled rail vehicle's operation.

Boiler

Boiler

A boiler is a closed vessel in which fluid is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central heating, boiler-based power generation, cooking, and sanitation.

Firebox (steam engine)

Firebox (steam engine)

In a steam engine, the firebox is the area where the fuel is burned, producing heat to boil the water in the boiler. Most are somewhat box-shaped, hence the name. The hot gases generated in the firebox are pulled through a rack of tubes running through the boiler.

Autotrain

Autotrain

The Autotrain was a type of passenger train used in the early 20th century, where the steam locomotive could be remotely controlled from the rear of the train. This meant that the engine would not have to run-around at the end of a journey before returning. These trains were also known as motor trains or railmotors at the time, but the term railmotor is now used to refer to trains where the steam engine was integrated into the coach.

DRG Class 05

DRG Class 05

The Deutsche Reichsbahn's Class 05 was a German class of three express passenger steam locomotives of 4-6-4 wheel arrangement in the Whyte notation, or 2′C2′ h3 in the UIC notation used in continental Europe. They were part of the DRG's standard locomotive (Einheitslokomotive) series.

4-6-4

4-6-4

Under the Whyte notation for the classification of locomotives, 4-6-4 represents the wheel arrangement of four leading wheels, six powered and coupled driving wheels and four trailing wheels. In France where the type was first used, it is known as the Baltic while it became known as the Hudson in most of North America.

Berlin–Hamburg Railway

Berlin–Hamburg Railway

The Berlin–Hamburg Railway is a roughly 286 km (178 mi) long railway line for passenger, long-distance and goods trains. It was the first high-speed line upgraded in Germany to be capable of handling train speeds of over 200 km/h (120 mph).

LNER Class A4

LNER Class A4

The Class A4 is a class of streamlined 4-6-2 steam locomotive designed by Nigel Gresley for the London and North Eastern Railway in 1935. Their streamlined design gave them high-speed capability as well as making them instantly recognisable, and one of the class, 4468 Mallard, holds the world record as the fastest steam locomotive. Thirty-five of the class were built to haul express passenger trains on the East Coast Main Line route from London Kings Cross via York to Newcastle, and later via Newcastle to Edinburgh, Scotland. They remained in service on the East Coast Main Line until the early 1960s when they were replaced by Deltic diesel locomotives; they themselves proving to be worthy successors to the A4s. Several A4s saw out their remaining days until 1966 in Scotland, particularly on the Aberdeen – Glasgow express trains, for which they were used to improve the timing from 3.5 to 3 hours.

FS Class 670

FS Class 670

The Rete Adriatica Class 500, classified after 1905 in the Ferrovie dello Stato Italiane as Class 670 was an unorthodox and iconic cab forward 4-6-0 (2'C) steam locomotive.

4-6-0

4-6-0

A 4-6-0 steam locomotive, under the Whyte notation for the classification of steam locomotives by wheel arrangement, has four leading wheels on two axles in a leading bogie and six powered and coupled driving wheels on three axles with the absence of trailing wheels.

Franco-Crosti boiler

Franco-Crosti boiler

The Franco–Crosti boiler is a type of boiler used for steam locomotives. It was designed in the 1930s by Attilio Franco and Dr Piero Crosti. The main difference between it and conventional feedwater heaters widely used on the continent is that the Franco-Crosti boiler uses both exhaust steam and exhaust gases from the firebox. Conventional feedwater heaters only use exhaust steam.

Automobiles

The AMC Pacer's forward placement of the passenger compartment

The Dodge Intrepid is one of the best known examples of cab forward design in automobiles

The cab forward design allows the passenger volume to be larger than in other similar sized automobiles.^[9]

The first modern mass-produced U.S. automobile using the cab forward concept was the Pacer, introduced in 1975 by American Motors Corporation (AMC).^{[10][11][12][13]} The company did not call it "cab forward", but the Pacer's layout placed the passenger compartment farther forward than was typical to that time.^[14] Its A-pillars were moved forward and the windshield was placed over part of the engine compartment. The Pacer's "wide track and cab forward design actually lets it handle pretty well" given its body roll like competing contemporary models.^[15]

Cab forward was used by Chrysler Corporation starting in 1992 to describe styling and engineering features that were similar to those seen on the AMC Pacer and the Lamborghini Portofino, which improved cornering and interior space^[16] The passenger cabin was "pushed forward" so that the front wheel well directly abutted the leading edge of the front doors, and the windshield extended forward over the engine, while the rear wheels were shifted towards the back corners of the vehicle. Moving the wheels to the edges allowed designers to enlarge the interior while improving ride and cornering.^[17]

Numerous models built from 1993 to 2004 on the Chrysler LH platform, the JA and JR platforms ("cloud cars"), and the PL platform (Neon), were specifically marketed as cab forward cars. Chrysler claimed to be the first to apply these features to a full-size car.^[18] Likewise, the Dodge Stratus and Chrysler Cirrus have a hood that is wider than it is long because engineers established a goal of packing the engine and everything else that is located ahead of the passenger compartment into a much smaller space and then the designers developed the car's outer body to offer more interior roominess than competing models in their size class.^[17]

Commercial vehicles

Tatra 815 version with low cab, situated in front of the engine

In road vehicle design, cab forward, also known as cab-over, COE (Cab Over Engine), or forward control, is a body style of truck, bus, or van that has a vertical front or "flat face", with the cab sitting above the front axle. This body design allows for a more compact configuration. For example, the Jeep Forward Control model was the first time the payload (or pickup box) had a record-breaking 74 in (1,880 mm) length (with the tailgate up) on an 81 in (2,057 mm) wheelbase as well as the first time offering a model where a 9-foot (274 cm) box exceeded the wheelbase of a truck.^[19]

The cab forward truck configuration is currently common among European and Japanese truck manufacturers, because the laws governing overall vehicle lengths are strict and the body style allows longer trailers or a longer cargo area for the same overall length than a standard truck (with an engine compartment ahead of a conventional cabin). Better visibility and maneuverability in tight quarters, such as for city delivery, are benefits of locating the truck's cab up front. Large trucks of this type are most often described as cab over engine (COE) or cab over models.

Discover more about Road transport related topics

AMC Pacer

AMC Pacer

The AMC Pacer is a two-door compact car produced in the United States by American Motors Corporation (AMC) from the 1975 through the 1980 model years. The Pacer was also made in Mexico by Vehículos Automotores Mexicanos (VAM) from 1976 until 1979 and positioned as a premium-priced luxury car.

Dodge Intrepid

Dodge Intrepid

The Dodge Intrepid is a full sized front-wheel drive four-door sedan that was produced by Dodge for model years 1993 to 2004. It is related to the Chrysler 300M, Chrysler Concorde, Chrysler LHS, Chrysler New Yorker, and Eagle Vision which were all built on Chrysler's new "cab forward" LH platform.

Chrysler

Chrysler

Stellantis North America, officially FCA US and formerly Chrysler, is one of the "Big Three" automobile manufacturers in the United States, headquartered in Auburn Hills, Michigan. It is the American subsidiary of the multinational automotive company Stellantis. In addition to the Chrysler brand, Stellantis North America sells vehicles worldwide under the Dodge, Jeep, and Ram nameplates. It also includes Mopar, its automotive parts and accessories division, and SRT, its performance automobile division.

Lamborghini Portofino

Lamborghini Portofino

The Lamborghini Portofino is a concept car developed for Lamborghini by Kevin Verduyn, one of Chrysler's chief designers. Introduced at the 1987 Frankfurt Auto Show, it was a fully functional, four-door, four-seat sport sedan.

Chrysler LH platform

Chrysler LH platform

The LH platform served as the basis for the Chrysler Concorde, Chrysler LHS, Chrysler 300M, Dodge Intrepid, Eagle Vision, and the final Chrysler New Yorker. A Plymouth to be called the "Accolade" was planned, but never saw production. The platform pioneered Chrysler's "cab-forward" design; featured on some Chrysler, Dodge, and Eagle cars in the 1990s and early 2000s.

Chrysler JA platform

Chrysler JA platform

The JA platform was Chrysler's smaller complement to the LH cars which were larger than the Ks, and a direct size replacement for the last extended K cars, the Acclaim and Spirit. It was a mid-size front-wheel drive automobile platform that was the basis for the Cloud Cars - the Chrysler Cirrus/Dodge Stratus/Plymouth Breeze starting in 1994. Like the LH, it was a cab forward design. While this platform was numerically successful, the highest volume for family cars competing against cars like the Taurus, Accord, or Camry would move to the LH platform cars, which were often classified as full-size.

Chrysler Neon

Chrysler Neon

The Chrysler/Dodge/Plymouth Neon is a front-engine, front-wheel drive compact car that was introduced in January 1994 for model year 1995 by Chrysler's Dodge and Plymouth divisions in two- and four-door bodystyles over two generations.

Marketing

Marketing

Marketing is the process of exploring, creating, and delivering value to meet the needs of a target market in terms of goods and services; potentially including selection of a target audience; selection of certain attributes or themes to emphasize in advertising; operation of advertising campaigns; attendance at trade shows and public events; design of products and packaging attractive to buyers; defining the terms of sale, such as price, discounts, warranty, and return policy; product placement in media or with people believed to influence the buying habits of others; agreements with retailers, wholesale distributors, or resellers; and attempts to create awareness of, loyalty to, and positive feelings about a brand. Marketing is typically done by the seller, typically a retailer or manufacturer. Sometimes tasks are contracted to a dedicated marketing firm or advertising agency. More rarely, a trade association or government agency advertises on behalf of an entire industry or locality, often a specific type of food, food from a specific area, or a city or region as a tourism destination.

Full-size car

Full-size car

Full-size car—also known as large car—is a vehicle size class which originated in the United States and is used for cars larger than mid-size cars. It is the largest size class for cars. In Europe, it is known as E-segment or F-segment.

Cab over

Cab over

Cab-over, also known as cab over engine (COE), cab forward (U.S.), flat nose (Canada), or forward control (UK), is a body style of truck, bus, or van that has a vertical front, "flat face" or a semi-hood, with the cab of the truck sitting above the front axle. This contrasts with a conventional truck where the engine is mounted in front of the driver.

Bus

Bus

A bus is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for charter purposes, or through private ownership. Although the average bus carries between 30 and 100 passengers, some buses have a capacity of up to 300 passengers. The most common type is the single-deck rigid bus, with double-decker and articulated buses carrying larger loads, and midibuses and minibuses carrying smaller loads. Coaches are used for longer-distance services. Many types of buses, such as city transit buses and inter-city coaches, charge a fare. Other types, such as elementary or secondary school buses or shuttle buses within a post-secondary education campus, are free. In many jurisdictions, bus drivers require a special large vehicle licence above and beyond a regular driving licence.

Axle

Axle

An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle is supported. In the latter case, a bearing or bushing sits inside a central hole in the wheel to allow the wheel or gear to rotate around the axle. Sometimes, especially on bicycles, the latter type of axle is referred to as a spindle.