FS Class E646

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FS class E646

Unit E646.094 in XMPR livery
Power type	Electric
Builder	TIBB
Build date	1958-1967
UIC classification	Bo-Bo-Bo
Wheel diameter	1.250 m
Wheelbase	13.550 m between bogies 2.580 m between axles in each bogie
Length	18.290 m
Width	3.013 m
Height	4.296 m
Locomotive weight	110 tons
Electric system(s)	3,000 V DC
Curent collection method	Pantograph
Traction motors	DC
Transmission	25/64 gear ratio
Top speed	140 km/h
Power output	hourly: 4,320 kW - continuous: 3,780 kW
Tractive effort	233 kN
Safety systems	RSC4; some units (about 40) have also been fitted with SCMT
Career	FS Trenitalia
Number in class	198
First run	1958
Disposition	In service

FS class E645

Unit E645.017 in its original livery.
Power type	Electric
Builder	TIBB
Build date	1957 – 1967
UIC classification	Bo-Bo-Bo
Wheel diameter	1.250 m
Wheelbase	13.550 m between bogies 2.580 m between axles in each bogie
Length	18.250 m
Width	3.013 m
Height	4.296 m
Locomotive weight	110-112 tons
Electric system(s)	3,000 V DC
Traction motors	DC series
Transmission	21/68 gear ratio
Top speed	120 km/h
Power output	3,780 kW
Tractive effort	286 kN
Safety systems	RSC4
Career	FS Trenitalia
Number in class	97
First run	1958
Disposition	In service, decommissioning

The FS E645 and E646 are two classes of similar electric locomotives used on Italian railways. They were introduced during the 1950s and, as of 2005, they are still in service.

E646 locomotive in its last livery.

[edit] History

The E646 and E645 locomotives project was started in 1953, with a new model engine that was to be installed on the modified chassis of the already-existing six-axle locomotive E636. A similar concept for a 4-axle locomotive led to the development of the E444 high-speed locomotive in the 1960s.

The first prototypes were delivered in October 1958. The first thirty-seven individual locomotives differed only in their livery: twenty built for passenger traffic were painted in grey-green, while seventeen built for goods were painted in auburn. Later, the freight locomotives were reclassed E645. The total number of locomotives built amounted to 295 units.

Several locomotives from each class are still in service with FS Trenitalia, on push-pull services, and many have been converted in E645 and assigned to goods services. They are scheduled to be retired, being substituted by E464 engines on regional services.

[edit] Technique

Class E646 doesn't follow the standard Italian class numbering rules. were the last digit indicates the numer of motors, as it mounts 12 two by two mechanically coupled 82-333FS type electric motors, each providing 360 kW, fed from the 3000 V catenary. These motors are more powerful than those mounted on the predecessor E636 class and able to improve performance up to 50% with only 20% more of weight; this also increases the overall adhesive mass of the locomotive, giving it better hauling performances.

Maximum speed is 140 km/h for the E646. The E645 has a different gear rate — 21/68 instead of 25/64 — with maximum speed reduced to 120 km/h, but with higher tractive effort. The locomotives weights 110 (E645: 112) tonnes.

To reach higher speeds, the motors can be connected in four ways: ^[1]

Due to the intrinsic property of the DC motors to absorb very high currents at low speeds, a rheostat needs to be connected in series to the traction motors when starting the train, to avoid an excessive flow of current to them. The aforementioned rheostat is gradually excluded as speed builds up and is also reintroduced when a transition to another motoric combination is made; like almost every Italian electric locomotive since E626, rheostatic exclusion is commanded through a controller (formed by a lever mounted on a curved notched support, commonly called respectively "maniglione" and "roncola" in Italian) subdivided into several notches, each representing a portion of the rheostat, plus four (one for each combination) special intermediate "end combination" notches.

Image of E646 cab fitted with SCMT; notable is the characteristic lever of most Italian rheostatic locomotives.

The driver gradually excludes the rheostat by rotating the lever counterclockwise, paying attention to not exceed the maximum allowed current (in this occurrence, the "maximum current relay", and consequently the Main Breaker (IR, Interruttore Rapido) opens), until he reaches the end combination notches, meaning that the rheostat is fully excluded for that combination; at this point, he can pass to the following combination or insert the field weakening shunts to further increase current. There are 31, 11, 9 and 8 notches on the roncola, each representing a portion of rheostat in the respective combinations.

In the 1960s the E646 locomotives were updated with the standard 78-wire cable, fire extunguishing system and automatic rheostatic exclusion system (Avviatore Automatico) to permit remote commanding by driving coaches on commuter push-pull passenger services.

Air production is granted by two 1000 lt. compressors, that fill the main tanks used by the braking system and other components (horn, whistle, contactors etc.).

Main auxiliary sevices also comprehend the 3000 V motor cooling fans, which also are used as generators to produce current used to recharge the 24 V DC batteries, that feed the low tension devices (lights, relays, solenoid valves, etc.).

Some units have also been fitted with static converters to feed aux. services and recharge batteries.

Like all non-electronic Italian locomotives, E646 are technically simple; driving personnel can often easily fix problems and get the locomotive moving for enough time to end the service or at least free the tracks.

[edit] Modified E645s

For testing purposes, units E645.016 and 017 were built with an even shorter gear ratio (20/69), that allowed a maximum speed of 110 km/h. These units were intended to be used for hauling heavy trains on steep lines. This modify wasn't applied on other E645s, however units 016 and 017 remained on regular service with their gear ratio for many years. Unit 016 was scrapped prematurely, as being involved in "Murazze di Vado" (see below) accident in 1978, while unit 017 received the usual 21/68 ratio in the first half of 1990s; however it retained the shorter roncola with considerabily less notches than the usual E645/6 ones.

[edit] Accidents

On April 15th 1978 an accident involved units E645.016 and E636.282 in Murazze di Vado (Bologna): the train hauled by these two locomotives derailed on a landslided tract and ended poised over a slope. When the first rescue had already arrived, both locomotives were hit by an ALe601 EMU on the express service "Freccia della Laguna"; the coaches fell into the slope, while the locomotives amassed one over each other by side. The accident caused 32 deaths and 120 hurt people. On the train was also present Verona's footbal club, unscathed because at the time of the accident, they were having lunch into the reastaurant wagon. After the accident, E645.016 was scrapped.

In Florence Firenze Castello station, on march 23rd 1998, unit E646.009 was hit by EMU ETR 480-34, that was running between Rome and Bergamo, and that passed a signal at danger without stopping (SPAD); the accident caused 1 dead and 39 hurt people. The E646 was later decommissioned.

First series E645, with edgy FS Class E636-like cabin.

E646 hauling a freight train.

[edit] Sources

[edit] See also

• FS Class E636
• FS Class E424
• FS Class E656
• FS Class E464