The Basics of TRAXXology: A general technical overview of Bombardier's TRAXX locomotives

Entry posted by NGT6 1315 August 28, 2012

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Morning all!

Most recently, I was thinking whether it might, in fact, be more suitable to change my approach towards writing articles about locos belonging to a type family, as I already have more than one Bombardier TRAXX and Siemens Eurosprinter type loco each. My idea would be to provide something of a "core" article with all relevant basic information about either family, in order to be able to offer this as a reference for all future model presentations. I'm going to begin the changeover to this structure with this slightly rewritten variant of an earlier entry on this blog, which I am going to amend with a few prototype photos I was able to take over time.

In terms of product history, Bombardier rolled out the original TRAXX design in 1999, at that time initially offering only the F140 AC1 type which became known as class 185 in German service. It was derived from the earlier class 145 medium freight locomotive, which in turn had also spawned the class 146 regional passenger loco. Consequently, many of the following technical descriptions can also be applied to these forerunners. Along with the original 185, a "new" class 146 was produced as well, and designated the P160 AC1 type. As had been the case on the 145/146 product line, both classes were largely identical, with major differences including quill drive bogies on the 146, and nose-suspended motors on the 185. Of course, the 146 again carried some specific equipment for passenger services, including, but not limited to, destination displays above the windscreens.

Production of this 1st generation ended in 2005, for a brief time being paralleled by the first 2nd generation locos built on the same production line, which were introduced in 2004. This production line is, in fact, being kept open as Deutsche Bahn are still holding an option for additional numbers of 2nd generation class 146 locos to be produced as required.

However, the 3rd TRAXX generation - which but is designated by Bombardier as the "2E" generation, "E" meaning "evolution" - followed quite soon, with production commencing in 2006 and continuing till this day. As in the previous two generations, various configurations for either full electric and indeed diesel-electric operation are available, and outlined in slightly greater detail further down in this post.

At this time, upcoming TRAXX versions include the AC3 type, which will be equipped with a "Last Mile" diesel-electric propulsion package to allow this fully electric loco independent operation at limited speed in non-electrified terminals and depots. With loco leasing enterprise Railpool being the launching customer, this type will be designated class 187.

In addition, Deutsche Bahn have ordered an initial batch of twenty improved diesel-electric TRAXX locos, which will be equipped with four small diesel motors rather than one large prime mover. This will allow the loco to operate on one to four working diesel motors as required at any time during the trip, and thus offer reduced fuel consumption, reduced noise emissions and less pollution. These locos will be designated class 245, and are expected to be delivered beginning in 2013.

Technically, all TRAXX locos to have appeared thus far share a large proportion of characteristics and design features, so I believe I can reasonably concentrate on these common items and point out differences only as required.

The body is fully welded and includes the underframe as an integral part. The latter consists of two longitudinal beams, two outer transversal beams at the ends which double as headstocks, as well as two pairs of additional transversal beams serving to support the secondary suspension springs as well as the underfloor transformer. The latter pair also comprises the bodyside traction bar pivots. The floor is strengthened by a number of additional, smaller support beams. Meanwhile, the body sides and cabs are separate assemblies, welded to the frame, while the roof is split into three independently removable segments made of aluminium. The body is designed to withstand longitudinal forces of 2,000 kN, with all internal installations being capable of withstanding impacts of 5 g longitudinally, 1 g transversally and 2 g vertically. Ventilation grilles for the traction motor blowers and transformer and inverter coolant circuits are provided in the angled roof planes, with the grilles also including dirt and moisture interceptors.

The bufferbeams feature the usual set of UIC-compliant buffers, chain link couplers and brake pipes as well as ETS and ECP sockets.

Roofside equipment is quite different in complexity when comparing the various TRAXX generations. While the class 145 and 146.0 electrics - sometimes unofficially referred to as "Baby TRAXX" as they preceded the actual TRAXX design, but do share numerous details with it - had very little on their rooftops aside from one pair of Stemmann DSA 200 pantograph, overvoltage arresters, radio antennae and horns, changes to the body design on the actual TRAXX required that a greater proportion of items be located visibly on the roof. While the high voltage busbar could be hidden inside the roof on the Baby TRAXX, it had to be laid along the outer roof surface on the TRAXX 1 and 2 as the roof had to be lowered on these types to allow for operations in countries where the national variations of the UIC loading gauge required a lower roof height. Also, both these types were prepared for two pairs of pantographs to be installed - one with the knee joints facing inwards, and the other facing outwards and located immediately over the cabs.

With the introduction of the TRAXX 2E, then, the requirement to accommodate equipment for AC and DC OHLE systems alike left the designers no other choice but to set the AC and DC busbars atop insulators. However, Bombardier were able to keep the circuit breakers inside the body. The fully electric TRAXX 2E locos are also designed to carry either two or four pantographs, though with the difference of AC pans generally being located on the outer positions, and DC pans on the inner ones.

The bogies are suspended from the locomotive's body by way of one pair of helical Flexicoil springs per side, and were developed on the basis of those used on the class 128 prototype. One principal difference between TRAXX types primarily designed for passenger or freight work respectively is that the former have quill drives derived from the "Gealaif" design - this designation being a palindrome of "AEG", with the remaining four letters describing the assembly as a "Lokantrieb mit integriertem Fahrmotor", which translates as "Locomotive Drivetrain with Integrated Traction Motor." Here, traction motor and gearbox have a unified casing, with the pinion having bearings on both sides, thereby reducing mechanical stress on the rotor shaft. This applies to all class 146.0, .1 and .2 locomotives as well as the class 246 passenger diesel locos, while all other TRAXX locomotives have nose-suspended motors - the German term for this type of drivetrain being "Tatzlager" drive.

Meanwhile, the bogie frame consists of two longitudinal and three transversal beams, two of these on the outer ends of the bogie and one in the centre,which also serve to carry the traction motors. The transversal beam on the inner end also has the traction bar pivot attached to it, with the bodyside pivots being located on the same beams also carrying the transformer. Finally, the wheelsets are held in outside bearings suspended from the bogie frame by way of two helical springs per bearing and levers attached to consoles located towards the centre of the bogie.

Like all contemporary German-designed electrics, the TRAXX has both pneumatic and electrodynamic brakes. The former are a standard Knorr type with settings G, P and R, and laid out with cheek disks mounted on both sides of each wheel, with the disks being clasped by calliper-like brake units with double-sided pads. Meanwhile, the dynamic brake is set up to be able to recuperate energy and feed it back into the grid on fully electric TRAXX locos and as a rheostatic brake on diesel-electrics, and takes precedence over the pneumatic brake through most of the loco's speed range. One brake cylinder per wheelset is set up with an additional spring unit to serve as a parking brake.

One screw compressor provides compressed air for all pneumatic systems on board, including the brakes, pantographs, circuit breaker, sanding units, flange greasers, horns and air conditioning units. There also is an auxiliary piston compressor able to run off the onboard batteries and provide sufficient air for raising the pantographs and closing the circuit breaker.

The transformer is hung under the loco's frame and cooled by a polyester-based liquid. It is connected to the traction inverters ? of which there is one per bogie ? consisting of two H bridges, common intermediate DC link and pulsed inverter. They, too, are liquid-cooled. Additionally, there are two auxiliary inverters, one providing fixed frequency three-phase AC for items like coolant pumps and the compressors, while the other provides variable frequency three-phase AC for the traction motor and cooling tower blowers. The heat exchangers for the transformer and inverter coolant circuits are stacked inside said cooling towers. Backup power for the most basic systems is provided from lead-acid batteries. The traction motors are four-pole squirrel cage asynchronous three-phase AC designs with forced ventilation.

The loco's control suite is based on the ADtranz MITRAC distributed control system, comprising two redundant control computers, connected to the various onboard devices by way of a so-called Multifunction Vehicle Bus. The system also comprises the "DAVIS" visual diagnostic interface to aid both the driver and works staff in troubleshooting.

As stricter crashworthiness norms were agreed on at the EU level while production of 1st generation TRAXX locomotives was still ongoing, Bombardier went ahead and developed a modified locomotive body for their 2nd and 3rd generation TRAXX. Specifically, the cab sections were re-designed to allow for better impact energy absorption capacities, with other visible details in this area including the cab air conditioning units having been placed behind swing-up doors in the fronts, and the windscreen wipers having been changed from a radial to a pantograph type. The remainder of the 2nd generation TRAXX body is largely identical to that of the 1st generation.

Inside, there are various other differences. With the Baby TRAXX having had a power output of 4,200 kW, 1st and 2nd generation TRAXX locos have been augmented to 5,600 kW ? though there is a plan to also upgrade the DB Regio 146.0s to provide the same output. However, 2nd generation locos were given improved inverters, based on IGBT modules rather than the GTO ones used on the Baby TRAXX and 1st generation locos. Several interior installations were rearranged as well, the pneumatic components being of particular notice. Finally, the 1st and 2nd generation TRAXX were given modernised cabs, with the MFA speed/tractive effort/train protection system display unit of the Baby TRAXX having been replaced by a third LCD screen. This, of course, was due to the locos having been expected to operate in non-German-speaking countries as well, where screens would make it easier to display information in different languages.

The 1st and 2nd generation TRAXX locos have since proven to be very successful, with 372 1st generation locos and more than 300 2nd generation locos having been built for various operators both from Germany and from abroad. In 2006, the first 3rd generation TRAXX loco was rolled out. As previously mentioned, this generation is usually referred to as TRAXX 2E, and uses a slightly modified variant of the 2nd generation body, but has a largely different interior arrangement. These differences became necessary due to Bombardier having intended to also offer diesel-electrics based on the TRAXX design. While the general outline of the loco's body is mostly identical to that of the 2nd generation, the engine room sides are split into three independent panels on either side, with the 2nd panel viewed from the Cab 1 end being replaced by air intakes on diesel-electric TRAXX locomotives. Also, there is a recess for a fuel filler tube on both sides of the body, located right halfway down its length in the frame. This recess but is not blanked over on fully electric locos. The inverter package is now mounted on a central position inside the engine room rather than on either side of a central corridor, with diesel-electric TRAXX 2E locos having a combined prime mover/inverter package in this place.

As previously mentioned, there also are specific type designations used by Bombardier for the various types of locomotives from their TRAXX family. These are the following:

F140 AC1: 1st generation freight locomotive (e.g. German class 185)

P160 AC1: 1st generation passenger locomotive (class 146.1)

F140 AC2: 2nd generation freight locomotive (e.g. German class 185.2)

P160 AC2: 2nd generation passenger locomotive (German class 146.2)

F140 MS: 2nd generation AC/DC quad system locomotive (Swiss class Re 484)

F140 MS2: 3rd generation AC/DC quad system locomotive (e.g. German class 186)

F140 DE: 3rd generation diesel-electric freight locomotive

P160 DE: 3rd generation diesel-electric passenger locomotive

F140 DC: 3rd generation DC only freight locomotive (Italian class E.483 and Spanish class 253)

P160 DC: 3rd generation DC only passenger locomotive (Polish class E.583)

Note that there are no 3rd generation AC only locos as of yet.

All TRAXX locos share the following basic specifications:

Overall length: 18.9 m/62 ft

Overall width: 2.98 m/9.8 ft

Overall height: 4.39 m/14.4 ft for full electrics

Bo'Bo' configuration

Meanwhile, the following data depend on the exact type of loco:

Power output: 5,600 kW/7,510 hp on full electrics and 2,200 kW/2,950 hp for diesel-electrics.

Standard service weights are 85 tonnes for full electric TRAXX locos and 80 tonnes for diesel-electrics.

Top speed: 140 kph/87 mph with nose-suspended motors, 160 kph/100 mph with quill drive.

And here's the promised photo strip, showing a selection of TRAXX locos in their natural habitat, if you will...

While the 145 is, strictly speaking, not yet a TRAXX locomotive, I should like to present you with one of these anyway. This here is 145 027 working light and running through Thekla Station in Leipzig.

A 1st generation TRAXX, 185 096 is seen here rolling north at Riedstadt-Goddelau on 11 May. This is one of those numerous 1st generation 185s operated by DB Schenker which are equipped for working into Switzerland. Another significant batch of this type is configured for France.

And this is 185 266, a 2nd generation TRAXX loco working through Frankfurt's Southern Station. At this time, parts of the DBS 185.2 fleet have running rights in Austria as well as Denmark and Sweden - the latter being due to their cooperation with Swedish freight operator Green Cargo.

Another 2nd generation 185, 185 342 is seen here shunting at the Bischofsheim yard near Mainz.

metronom are a TOC from the state of Lower Saxony, who are currently holding the franchise for various regional lines in that state as well as out to Bremen and Hamburg. They also operate the Lower Elbe Railway from Hamburg to Cuxhaven, where I snapped 246 002 "Buxtehude" standing by to pull out an ECS to the sidings. This is a diesel-electric version of the 3rd generation TRAXX 2E type.