Afternoon all…

 

In today's posting, I should like to present a model which took a lot of time and patience to obtain as it has actually been out of production for an extended period of time. Consequently, I had been particularly happy when I had, in fact, been able to obtain an example of Roco's SBB Cargo class Re 421 at my favourite Swiss retailer, Wemoba.

 

 

Those of you who follow the Swiss railway scene will most likely be aware of the Swiss Federal Railways having begun introducing newly designed electric locomotives with all-bogie configuration in 1946. These Bo'Bo' configured locomotives, designated Re 4/4^I, with a 1,900 kW power output, service weight of only 57 tonnes and maximum speed of 125 kph (78 mph), were well suited for working formations of the "Lightweight Steel Stock" coaches introduced in 1937, as well as the post-war Standard Coach I ("Einheitswagen I") stock, but even in MU formation were insufficiently powerful for the increasing train lengths which had become standard by the late 1950s, and not well suited for anything but light passenger service on mountainous lines of which there are many in Switzerland. At the same time, the Co'Co' configured Ae 6/6 electrics which were first presented in 1952 and produced from 1955 till 1966, while powerful and reliable and well suited for difficult route profiles, could not be certified for the "R" speed category due to their long bogie wheelbase and high weight. SBB therefore tendered for an evolved, Bo'Bo' configured locomotive which was to be capable of working at Category R speeds throughout the Swiss railway network.

 

With the tender having been won by a consortium of the Swiss Locomotive and Machine Works (SLM) of Winterthur, Brown-Boveri of Baden, Oerlikon Machine Works (MFO) of Zurich and Sécheron of Geneva, six prototypes of this new locomotive – preliminarily designated only as "Bo'Bo'" – were rolled out in 1964.

 

While at that time, certification parameters in Switzerland technically precluded motive power with an axle load of more than 16 tonnes to be approved for Category R speeds, route trials with the "Bo'Bo'" revealed that in spite of their axle load of 20 tonnes their riding dynamics were so favourable that they could be certified for Category R. Consequently, they received the final designation of Re 4/4^II, and paved the way for the BLS Ae 4/4^II? – an evolved version of the original Ae 4/4 – to be recertified as Re 4/4 shortly afterwards. These locomotives, while not directly related to their SBB equivalents, had been developed during the same period, and therefore provided similar performance characteristics.

 

Production of the Re 4/4^II commenced in 1967, and ended only in 1985 when 276 examples had been built. Until today, these locomotives and the closely related Re 4/4^III subtype which will be addressed further down remain an important pillar of the SBB locomotive inventory, and have proven to be highly capable and reliable pieces of motive power.

 

 

Technical description

 

 

One item which is immediately obvious when looking at the „Bo-Bo Two“, as drivers still like to refer to these locos, is that they are quite compact, measuring only 14.8, 14.9 or 15.41 metres (48.5, 48.9 and 50.6 ft) in length respectively. The prototypes are the shortest of the lot, with the 1^st production batch measuring 14.9 metres and the 2^nd and largest batch ending up at 15.41 metres. The body had been thus lengthened after drivers had complained of a lack of leg space. This difference is easily visible when looking at the locomotives from the side, as the cab faces are noticeably more raked back on the 2^nd batch, which began with 11156.

 

On all three batches, the body is a self-supporting welded steel assembly consisting of the running frame, fronts, sides and the roof as the principal subassemblies. The roof also comprises three removable aluminium sections for better access and removal of large components. Three windows are present on both body flanks, while the ventilation grilles have been placed along the edge of the roof in order to reduce the amount of dirt being drawn into the engine room. Beginning with locomotive 11107, impact absorbers were installed behind the buffers in order to prevent the body from being deformed in light collisions at shunting speeds – the body itself being capable of withstanding a pressure of 200 tonnes without permanent damage. There is a Z-shaped corridor through the engine room connecting both cabs. On the bottom of the running frame, protective skirts are attached below the bufferbeams, while the frameside attachment bearings for the traction bars are located both ahead and inside of the bogies.

 

The bogie frames are welded assemblies consisting of two longitudinal and two transversal end beams, the latter of which are cast metal pieces. The primary stage suspension is provided by helical springs between the bogie frame and the axle bearings, with hydraulic motion dampers being provided and the wheelsets in turn being held in double roller bearings. The wheelsets are also allowed some degree of sideplay for better curve running, being able to be displaced by 10 millimetres to either side, with springs located inside the axle boxes providing a centring effect of 2,000 kilograms.

The secondary suspension assembly consists of two sets of three concentric helical springs per bogie – one on either side – with the upper ends being attached to a transversal beam on the underside of the running frame and the lower ends being attached to a transversal beam suspended below the bogie. This, in turn, is attached to the bogie frame by a set of vertical levers on either side, with additional transversal levers inside the bogie absorbing lateral forces and motion.

 

The two traction motors per bogie are mounted in a separate block casing which is attached to the bogie frame at the outer ends. Power transmission to the wheelsets is accomplished through a single-sided BBC type quill drive, with the gear ratio being 1/2.64 on the Re 4/4^II and 1/3.11 on the Re 4/4^III.

 

As previously indicated, traction bars are used to transmit tractive effort to the body. These bars are attached to a pair of bearings near the centre of the bogie on the underside of the traction motor block, and guided around the lower edges of the motor block by roller bearings, then to continue to the body attachment points which are located on pedestals behind the frontside skirts and immediately on the bottom of the frame between the bogies. There also is an inter-bogie coupler mechanism to allow both bogies to be more accurately steered through curved track.

 

The braking gear consists of two pneumatic cylinders per bogie, acting on two pairs of tread brake pads per wheelset.

 

On the bufferbeams, standard UIC couplers are provided, as are the usual pipes for the indirect pneumatic brake. In addition, there is a pair of pipes related to the direct brake circuit, allowing for locos coupled in a MU formation to be directly braked as a unit while shunting. Of course, ETS sockets are present as well, as are sockets for the MU and UIC jumper cables. The Re 4/4^II and Re 4/4^III types are both fitted for push-pull operation as well, but the Re 4/4^III is not permitted to be thus operated due to the different gear ratio and correspondingly higher forces having been determined to increase the risk of derailing a pushed train.

 

Eight Re 4/4^IIs were specially fitted for the so-called “Swiss Express” formations which were used on the Geneva – St. Gallen services between 1974 and 1982. These were composed of the EW III (EW meaning “Einheitswagen” or “Standard Coach”) coaches. Ther EW III coaches were initially intended to be equipped with a tilting mechanism, which but was never enabled in regular service. These formations were not normally uncoupled except for removing individual coaches for repairs, for which reason the outermost coaches were designed as dedicated end coaches with no outer gangway doors. These end coaches were also fitted with knuckle couplers on either ends for shorter turnaround times at termini, requiring that a number of Re 4/4^IIs be identically fitted. Eight 1^st batch locomotives – 11103, 11106, 11108, 11109, 11112, 11113, 11133 and 11141 – were chosen for this refit and were given extended bufferbeams with knuckle couplers, as well as the same livery as the EW III coaches, which was orange/light grey/orange in three broad horizontal stripes. This refit but restricted these eight locomotives to working EW III formations only, as no other coaches were ever similarly outfitted with knuckle couplers.

 

In 1982, the “Swiss Express” formations were rebranded as normal InterCity workings, and both the coaches and the eight Re 4/4^IIs were fitted with UIC couplers. Also, seven 2^nd class EW III coaches were rebuilt into driving trailers, eliminating the need for loco changes.

 

The EW III sets were sold to BLS in 2004, along with a number of Re 4/4^IIs. The coaches are now used on regional express services in the Berne/Lucerne area, and can also be found coupled to the powerful class Re 465 locomotives.

 

Another important version which was created only in recent years are the SBB Cargo locomotives Re 421 371 through 381 and 383 through 397. This batch is fitted with a 1,950 mm Schunk WBL 85 pantograph and the German PZB and LZB train protection systems, enabling them for operation in Germany. However, as the German Federal Railway Authority had requested a full set of certifications for the spoked wheels to be able to withstand 140 kph running, the Re 421s are restricted to 120 kph on the German network as SBB Cargo determined 120 kph were sufficient for the freight services these locomotives were to provide primarily.

Several years earlier, 11195 through 11200 had been outfitted with a specially designed 1,950 mm pantograph, which allowed these six locos to work into Lindau and Bregenz on the shore of Lake Constance on international services. However, they were not fitted with the PZB train protection system as used in Austria and Germany, and were issued a restricted certification valid only for those lines connecting Switzerland, Bregenz and Lindau. When the Re 421 type was created, these locomotives took over the cross-border services in the Lake Constance area as well, following which 11195 through 11200 were rebuilt as normal Re 4/4^IIs.

 

As for the electrical part, the Re 4/4^II and Re 4/4^III are classical single phase AC locos, using tap changers for power control. The first thing to be considered here is how the 1^st batch locomotives were initially fitted with a single BBC 350/2 type diamond pantograph on the Cab 1 end, while the 2^nd batch ones were fitted with a pair of BBC ESa 06-2500, 22-2500, ESaD 22-2500 or EKa 05-2560 type single arm pans located over both cabs. The remaining roofside equipment includes the air blast circuit breaker which is located in the centre section, and has a cutoff switch added which is to be used when earthing is required. Some 1^st batch locos were refitted with a single ESa 06 pantographs in later years.

 

The transformer, located centrally in the locomotive room, has output taps for the traction motors as well as the ETS and auxiliary circuits, providing 4,000, 500 and 80 kVA respectively. The tap changer, designed as an “up/down” impulse type, is located on the primary side of the transformer in order to limit current load, and has 32 notches which are switched by way of a pneumatic motor with four cylinders. The traction motors are connected in parallel, have ten poles and feature a continuous shaft power output of 1,113 kW, at a rated continuous current of 2,300 A, continuous tension of 525 V and speed of 1,200 rpm.

 

The auxiliary equipment, which is connected to the 240 V circuit, includes two traction motor ventilation blowers, the compressor, a 36 V static inverter for the battery charging circuit, the transformer coolant oil pump, cab heating and a OHLE voltage sensing device. The ETS circuit is fed with 1,000 V. The traction motor blowers have two speed settings, with the “low” setting being active at speeds up to 30 kph and as long as the tap changer is not beyond Notch 5.

 

The locomotives are also fitted with a regenerative electrodynamic brake which was designed around the requirement of being able to maintain speed while descending the southern ramp of the Gotthard Railway at the head of a 400 tonnes train for a duration of about 40 minutes, unassisted by the pneumatic brake.

 

The cabs feature a control desk located on the left side, as is the case on most Swiss-built locomotives. They were designed around a new control concept first tested on the class RBe 4/4 EMUs 1401 through 1406, with the “steering wheel” style power controller used up till the Ae 6/6 having been replaced by a horizontally moving lever which was placed on the driver's right-hand side. The indirect and direct brake valves – which are Oerlikon FV4a and FD1 types – are located to the left, with most other control switches and indicator lamps being located in front of the driver’s position. The speedometer, brake gauges, voltmeters and ammeters are located in and above the upper plane of the control desk, in this order when looking left to right.

One thing which should be mentioned in this context is that 11299 through 11304 were fitted with a Swiss variant of the LZB cab signalling system for evaluating purposes, though this system was never introduced to the Swiss railways on a large scale and, in fact, eventually dismantled after the trial phase ended. These six locomotives – plus 11305 through 11349 and 11371 through 11397 – feature a ribbon-style speedometer. Today, all Re 4/4^IIs are equipped with the Integra-Signum and ZUB 121 train protection systems, and have also begun to be refitted with ETCS onboard units emulating Integra-Signum and ZUB 121 functionality.

 

The Re 4/4^II, geared for a top speed of 140 kph (87 mph) and initial tractive effort of 255 kN (57,326 lbf), was supplemented by an additional variant which was designed to offer higher overall tractive effort for heavy passenger and freight workings across the Gotthard and Lötschberg lines. This type was created in 1966 when Südostbahn, one of the larger private operators in Switzerland at the time, ordered a single Re 4/4^II locomotive geared for a top speed of 125 kph (78 mph) and tractive effort of 280 kN (62,946 lbf). This variant piqued SBB's interest and led to a subsequent order of twenty such locomotives, designated Re 4/4^III.

Three of the SBB Re 4/4^IIIs were sold to Südostbahn between 1983 and 1985 but bought back from 1994 till 1996 in exchange for the four Re 4/4^IV locomotives, which unlike the Re 4/4^III were able to work push-pull trains with no restrictions.

 

At present, the Re 4/4^IIs are also known by the UIC-compliant designation of Re 420 – and Re 421 for those locomotives outfitted for Germany – while the Re 4/4^IIIs are also designated Re 430.

 

 

Technical specifications (Re 421 only)

 

Length, width and height – 15.41 m, 2.97 and 4.5 m/50.6, 9.7 and 14.8 ft

Service weight – 85 tonnes/83.7 long tons

 

Power output – 4,700 kW/6,303 hp

Initial tractive effort – 255 kN

 

Maximum speed – 140 kph in Switzerland, 120 kph in Germany/87 and 75 mph

 

 

 

The model

 

?A variant of Roco's newly tooled long-bodied Re 4/4^II model, the Re 421 was marketed with catalogue no. #72404, representing 421 387 as she appeared roughly around 2009. This model is nicely detailed and gives an excellent impression of the rugged yet understatedly elegant appearance of these slightly diminutive but powerful electrics.

 

 

 

 

 

?The Re 421 is outfitted with a Schunk WBL85/15 pantograph on Cab 1, carrying a 1,950 mm head for compatibility with the German OHLE. Interestingly, those Re 420s refurbished for domestic passenger services as part of the "LION" programme are outfitted with the same pantographs with a 1,450 mm head, which have been recovered from the Re 460s which in turn are being outfitted with Faiveley AX pantographs for better high-speed running properties.

Furthermore, the Re 421s needed to be equipped with additional radio antennas for Germany, which are represented on the model also.

 

 

 

 

Beginning in the late 1980s, the Re 4/4^II and Re 4/4^III were refitted with sealed-beam combined head and tail lights in lieu of the original, round lower headlights. The Re 6/6s were thus refitted also. In this view, you will also get an impression of the characteristic cab face design which is typical of these classes, and which is also evident on Rhätische Bahn's Ge 4/4^II metre gauge electric locomotives.

 

 

 

 

 

?One single broadside photo should be sufficient here as the Re 421 really is quite compact. The lettering on the Cab 1 flank comprises the braking weights, giving different figures for Switzerland in the left column and for Germany in the right column:

 

Switzerland:

 

R 100 t

P/V 72 t

G/M 72 t

 

Germany:

 

R 95 t

P 68 t

G 64 t

 

Handbrake 2x 14 t (for either country)

 

The service weight is indicated as 85 tonnes and the revision indicated on the Cab 2 flank is dated to have been completed on 24 December, 2004, at the Bellinzona workshops.

 

 

 

 

 

 

 

The pantograph on Cab 2 is a finely detailed representation of the ESa 06 series pantograph provided on the Re 4/4^II. Also note the air blast circuit breaker being located between the second and third rooftop fairing, and the voltage sensing device and whistle between the first and second fairing.

 

 

And of course, this article would not be complete without a few Youtube videos with Re 421s at work. Thank you for your time!