FS E.323 and E.324

FS locomotives E.323 and E.324
FS locomotive E.323.018 in service at Genova Brignole railway station on March 10, 1996.
Type and origin Power type Electric Builder Tecnomasio Build date 1st series: 1966-1967; 2nd series: 1970-1971. Total produced 30 E.323 + 10 E.324
Specifications Configuration: ​  • UIC C Wheel diameter 1,040 mm (41 in) Wheelbase: ​  • Leading 4,000 mm (13 ft) (1,500 + 2,500 mm [4.9 + 8.2 ft]) Length 9,240 mm (30.31 ft) Height 3,700 mm (12.1 ft) Loco weight 46 tonnes (45 long tons; 51 short tons) Power supply Direct current at 3 kV Gear ratio 1:15.8 (Vmax32 km/h [20 mph]); 1:7.54 (Vmax 64 km/h [40 mph]).
Performance figures Maximum speed 64 km/h (40 mph) Power output: ​  • 1 hour 210 kW (280 hp)  • Continuous 190 kW (250 hp) Tractive effort: ​  • Starting 147 kN (33,000 lbf)  • 1 hour 91.2 kN (20,500 lbf) at 6.66 km/h (4.14 mph)  • Continuous 82.4 kN (18,500 lbf) at 7.44 km/h (4.62 mph)

The E.323 locomotives and E.324 motor trailers were two sets of 3000 V direct current electric locomotives of the Italian State Railways (FS) used for shunting service in large rail yards and in embarking and disembarking from ferries.

Unlike the E.323s, the E.324s were locomotives lacking the driver's cab and pantograph and were used in double traction with multiple control with the former to double their performance.

They constituted the sequel to the FS E.321 and E.322 classes, of which they resumed the design of the electrical part, updated on the basis of experience in operation and technological advances, while the mechanical part was designed from scratch.^[1]

In the early 1970s, as part of a collaboration between the FS and the Faculty of Engineering of the University of Rome "La Sapienza," it was decided to use a unit from the E.323 class to develop the design and testing of an electronic converter suitable for powering a three-phase traction motor, an idea later abandoned as a result of developments in power electronics related to the design of the E.402 locomotives. This would have been the world's first application of a three-phase traction motor to a 3 kV DC locomotive.

In the second half of the 1960s, the good operating results achieved by the E.321 and E.322 prompted the FS to extend the use of electric locomotives in shunting service. In developing the project, it was decided to keep the electrical part of their progenitors while it was decided to build from scratch the mechanical part (carriage, running gear and brake steering) following the design of the unified 245 locomotives (245.1001-1020, 2001-2020, 6010-6124). This solution, keeping the same GLM 2405 engine as the E.321 and E.322, made it possible to use a transmission with universal joints and telescopic shafts and to arrange the gearbox assembly with two gear ratios: the first to have a speed of 32 km/h (20 mph) suitable for shunting and the second to achieve a speed of 64 km/h (40 mph) suitable for hauling traction^[2] and for full line movements. The design, as with the E.321 and E.322, was developed by the FS with the collaboration of the Tecnomasio Italiano Brown Boveri (TIBB).^[3]

The construction of the electrical and mechanical parts was entrusted to Tecnomasio Italiano Brown Boveri. As with E.321, "motor trailers" controlled by E.323 and classified as E.324 were also designed and ordered, identical to the same E.323 but without a driver's cab (for this feature they were called "dogs" like E.322). Subclasses E.323.001-010 and 011-020 (delivered in 1966 and 1970–71), E.323.101-105 (delivered 1966-1967), E.323.201-205 (delivered 1971), E.324.101-105 (delivered 1966-1967) and E.324.201-205 (delivered 1971) were built.^[3][4]

Given the previous experience with E.321.200 and E.322.200, E.323.200 was designed and built with the ability to remote control two E.324.200s.^[3][5]

Between April and October 1967 the E.323.105, along with other locomotives, passenger railroad cars and wagons was exhibited in major Italian stations to present to the general public the renewal of the rolling stock underway as a result of the FS's Ten-Year Modernization Plan (1962-1972).^[6][7]

Locomotives E.323 and E.324 were subjected to a major repair every 40000 hours of service. In the middle of the interval an "R III" repair was interspersed, which did not involve complete disassembly of the car.^[8][9]

The E.323 and E.324 were always employed in shunting service, gradually going to replace the last steam shunting locomotives in the process of being phased out, flanking the Diesel locomotives and their direct progenitors E.321 and E.322, which had demonstrated full responsiveness to the onerous continuous duties on the launching saddles of the large marshalling yards.^[10]

In addition to services on the sidings of the station they were employed continuously in marshalling yards and in ferry boarding of trains to and from Sicily at Messina Marittima and Villa San Giovanni stations.^[11][12]

Because of their characteristics, they were only occasionally used for traction of the troop trains^[2][13] and in the middle of the line.^[14]

The performance in shunting service of the E.323 and E.324 locomotives is shown in the following table, taken from the General Preface to the Timetable of Service (PGOS)^[15] of the State Railways, which expresses the load in tons that can be hauled by the locomotives in shunting service, depending on the track gradient.

Tonnage performance of railcars and shunting locomotives in shunting service

Class	Gradient ‰						Power HP
	3	6	10	15	20	25
E.321 E.322 (1)	740	550	400	300	240	190	260
E.323 E.324 (1)	1050	770	560	420	340	260	260
(1) For the pairs E.321 + E.322 and E.323 + E.324, the performance is twice as much as shown in the table.

The performance in traction and full-line service of E.323 and E.324 locomotives is shown in the following table, taken from the General Preface to the Timetable of Service (PGOS)^[14] of the State Railways, which expresses the load in tons that can be hauled by locomotives in full-line service as a function of performance grade.^[16]

CLASS E.321 — E.322 — E.323 — E.324 — (1)

Speed	Performance grades of the lines
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24
50 km/h	65	60	55	50	45	40	35	30	25	25	—	—	—	—	—	—	—	—	—	—	—	—	—	—
40 km/h	145	135	125	120	110	110	95	90	80	75	65	60	55	50	45	40	35	30	25	20	—	—	—	—
35 km/h	210	200	185	175	165	160	145	135	125	115	105	95	85	80	75	70	60	55	50	45	40	40	35	30
30 km/h	310	290	270	255	240	225	210	200	180	165	150	140	130	120	110	105	95	90	80	75	70	65	60	55
25 km/h	440	410	385	360	340	320	300	280	260	240	220	200	190	180	170	160	145	130	120	110	105	100	95	90
20 km/h	620	570	535	500	475	450	425	400	370	340	315	290	270	250	235	220	205	190	180	170	160	150	140	130
(1) For the pairs E.321 + E.322 and E.323 + E.324, the performance is twice as much as shown in the table.

In January 1985, units of the E.323 and E.324 groups were distributed to the following depots:^[17]

• locomotives E.323.001-020, not apt to drive E.324s, were assigned to Torino Smistamento (1), Alessandria (2), Genova Brignole (3), Savona (1), Verona (2), Fortezza (1), Udine (1), Bologna (3), Florence (1), Pisa (1), Livorno (1), Ancona (1), Bari (1), Foggia (1);
• locomotives E.323 of the 100 and 200 series, suitable for driving E.324, were assigned to Alessandria (1), Milano Smistamento (2), Verona (1), Udine (1), Reggio Calabria (5);
• E.324 motor trailers normally followed E.323s of equal numbering, but the FS did not use to indicate their quantities at individual depots.

On December 31, 1991, all units of the E.323 and E.324 classes were still in service distributed in the following depots:^[18]

• locomotives E.323.001-020 were assigned to Alessandria (3), Genoa Rivarolo (3), Savona (1), Verona (2), Udine (1), Bologna (3), Pisa (3), Ancona (1), Rome San Lorenzo (1), Foggia (1), Reggio Calabria (1);
• E.323+E.324 complexes of the 100 and 200 series were assigned to Alessandria (3), Milano Smistamento (2), Verona (1), Udine (1), Foggia (1), Reggio Calabria (2).

According to Haydock^[19] in 1995 all units of both groups still existed and were assigned as follows:

• E.323.001-020 to Alessandria (3), Ancona (1), Bologna Centrale (1), Foggia (1), Genoa Rivarolo (3), Pisa Sant'Ermete (3), Reggio di Calabria (1), Rome San Lorenzo (1), Savona (1), Udine (1), Verona (4);
• the E.323,100 in Alessandria (2), Reggio di Calabria (3);
• the E.323.200 at Alessandria (1), Milano Smistamento (1), Udine (1), Verona (2);
• the E.324,100 at Alessandria (2), Reggio di Calabria (3);
• the E.324,200 at Alessandria (1), Milano Smistamento (1), Udine (1), Verona (2).

As of January 30, 2000, all units were in service, namely, thirty E.323s, assigned to the FS Regional (16), Passenger (3) and Cargo (11) Divisions and ten E.324s, assigned to the FS Regional (2), Passenger (2) and Cargo (6) Divisions.^[20][21]

They were shelved starting in 2002^[22] and decommissioned between October 2002 and June 2009.^[23]

To this day, locomotive E.323.010 still remains shelved for years at the Rimini Locomotive Depot in rather poor condition.^[24]

There still exists the E.323.105+E.324.105 complex in consignment to the amateur association AISAF based in Lecce.^[25]

On the basis of the favorable operating results of the E.321 and E.322 locomotives, which resulted in appreciable savings compared to the cost of Diesel traction units, the FS decided to purchase an additional batch of similar units, for which, however, a completely new mechanical part was developed to meet all the requirements of shunting service.^[26]

For the same reasons mentioned about the E.321 the Ward Leonard type scheme was retained^[27] using the same electrical machinery: 260 kW (350 hp) double-commutator primary engine powered at 3 kV, main generator^[28] of TIBB-CGE construction of 210 kW (280 hp) power at 1,250 rpm, at 460 V voltage and traction motor developing at continuous speed a power of 190 kW (250 hp) as well as at hourly speed a power of 210 kW (280 hp). The only variation introduced was the adoption of field weakening^[29] on the traction motor.^[30]

Significantly, without modifying the electrical machinery, the adoption of the two-speed gearbox assembly and the introduction of field weakening resulted in a significant increase in performance over the E.321 and E.322 locomotives, as can be seen from the extract from Table 45 of the PGOS given in the Services section.^[30]

Despite the excellent operating results mentioned above, the E.321 and E.322 locomotives suffered from the limitations imposed by an outdated mechanical part design, which was penalized by the connecting rod transmission and internal bushings with plain bearings.^[31]

In the design of E.323 and E.324 it was decided to overcome these drawbacks by adopting the same mechanical part developed for the new "unified" Diesel locomotives^[32] of class 245, characterized by:^[31][33]

• three wheelsets equipped with bushings outside the wheels, fitted with roller bearings and conformed to allow transverse displacement of the axles so as to allow inscription in curves with a minimum radius of 70 m (230 ft);
• suspension consisting of leaf springs superimposed on the bushings and connected to the chassis by adjustable hangers;
• a pair of rocker arms connected between the first two wheelsets;
• a mechanical device for automatic lubrication of the wheel flanges (De Limon type);
• a two-gear reduction unit (Hurt HSN 1200/2 type)^[34] positioned between the second and third wheelset, which allowed selection of maximum speeds of 32 or 64 km/h (slow or fast gear).

The gearbox unit was connected to the traction motor by means of a coupling with rubber spring elements and activated the drive decks^[35] (Hurt type HSK 19)^[34] mounted on each locomotive wheelset^[30][33] with universal joints.

In shunting, the slow gear was normally used, which allowed the highest tractive efforts to be generated up to the speed of 32 km/h (20 mph); in isolated locomotive trips or with limited load, the fast gear was used, which allowed up to 64 km/h (40 mph) with the tractive effort halved.^[30][36]

Switching between the two speed ranges could take place only when the locomotive was stationary by means of an electropneumatic device,^[31] which also allowed the speed reducer to be set in the "neutral" position, severing the mechanical connection with the traction motor when the locomotive had to be pulled by another vehicle.^[30]

The electrical part replicated the one of E.321 and E.322, with some modifications suggested to the designers by the experience of operation with the progenitors.^[37]

As with E.321 and E.322, the electric machines, with the exception of the wagon-mounted traction motor, were arranged on the front of the locomotive bed, inside the forebody.^[38]

The electrical equipment included a primary motor fed from the 3 kV DC overhead line and flanged on the main generator's armature shaft so as to form a one-piece unit with it. This unit drove by means of pulleys and V-belts another monoblock unit consisting of two DC generators, the first of which supplied the auxiliary circuits and recharged the batteries, while the second provided separate excitation to the primary motor. The same genset was used to drive the centrifugal fan that cooled the traction motor, while on the opposite side of the main unit the compressor was driven to power the pneumatic system and the brake circuit.^[39]

Conventional electrical equipment with a DC motor powered at constant voltage would have created serious limitations on a shunting service locomotive, both because of the rapid decrease in torque with increasing motor speed and because of the heavy energy dissipation on the starting rheostat.^[40] Moreover, the latter, being intended to run continuously engaged for frequent starts, would have had to take up a considerable amount of space. At the same time, the modest power required to perform this type of service made it almost obligatory to resort to a single traction motor, making impractical the technique, adopted on locomotives for line services, of obtaining speed regulation by connecting the motors in series and in parallel.^[26][41]

As in the case of the earlier E.321 and E.322 units, therefore, an equipment similar to that of the Diesel-electric locomotives was opted for, in which the Diesel engine would be replaced by an electric primary motor, thus obtaining a system similar to the Ward Leonard unit used in industrial drives,^[27] suitably adapted for railway needs.^[26][39]

Thus, the same structure made for the E.321/322 was confirmed, with minimal variations, consisting of a primary motor fed directly from the catenary at 3 kV mechanically coupled with a main generator,^[28] which in turn fed the traction motor with an adjustable voltage within wide limits, suitably varying its speed without resorting to the series rheostat.^[26]

Running adjustment was carried out by the driver by inserting a series of resistors into the excitation circuit of the main generator, obtaining for each position of the shunting combiner one of five curves, called "external characteristics," shown in red on the voltage-current graph shown in the figure.^[42]

The external characteristics obtained in this way exhibited strong voltage variations as the load current varied, which enabled the main generator to limit the traction motor's inrush current and automatically adjust its voltage during the acceleration phase, realizing without energy dissipation the same function as the starting rheostat of conventional locomotives.^[43]

The only variant introduced in the traction circuit compared with the locomotives of the earlier E.321 and E.322 classes was the adoption of field weakening on the traction motor, which entailed the addition of an electropneumatic contactor (see diagram) and the upgrading of the control circuit.^[30]

The addition of traction motor field weakening and speed selector (32 or 64 km/h (20 or 40 mph)) entailed the inclusion of the respective controls in addition to those on the E.321 shunting bench and the implementation of an interlocking circuit between the E.323 locomotive and the E.324 motor trailers to synchronize the position of the speed reducers on the coupled units.^[30][31]

The system for electric heating of coaches was not installed on any of the E.323 and E.324 units.^[34]

As with E.321/322, power for the auxiliary circuits was produced by a belt-driven DC generator from the primary engine, to the terminals of which was connected a voltage regulator that supplied the control, lighting and battery charging circuits.^[44]

Compressed air for the pneumatic controls and the brake circuit was produced by a Westinghouse 241-P type compressor^[34] mechanically driven by the primary engine, a solution that made it possible to eliminate expensive 3 kV motors for the motor compressors.^[39][42]

An electric compressor powered by the auxiliary generator or battery produced the air needed to raise the pantograph.^[44]

Compared with the electropneumatic circuit of the E.321/322^[44] were added:^[30][31]

• the solenoid valve for the speed selector control;
• the solenoid valve of the field weakening contactor.

Comparison with the Diesel-hydraulic 245 locomotives, with primary engine calibration power of 368 kW versus 260 kW of the E.323, resulted in slightly lower performance for the latter, as evidenced by the graph showing the tractive effort curves in the speed range between 0 and 32 km/h (0 and 20 mph); for speeds up to 64 km/h (40 mph) the tractive efforts are halved, but the operating conditions of the two types of locomotives remain practically unchanged.^[30]

Since no official data had been published, the economic evaluation was carried out by extrapolating the "hourly operating costs without the cost of train crews" related to the comparison of electric E.321 locomotives and Diesel 235 locomotives published in 1963, from which a 27% lower hourly cost between the former and the latter emerged (1 105 vs. 1 530 Lit/h).^[45][46][47]

Considering that the operating cost of the E.323s should not have varied from the E.321s, the machines being entirely similar, while the 245s should have entailed a greater expense for fuel because of the greater power of the Diesel engine compared to the 235s, it was estimated that at equal performance the operating cost of the Diesel locomotive was at least 40% higher than that of the electric locomotive.^[47]

Faced with such a considerable difference in costs and counting on the fact that no practical changes were necessary in the organization of services and facilities for electric shunting operation, the technicians of the Tecnomasio Italiano Brown Boveri (TIBB) prospected the State Railways (FS) to reflect on the convenience of augmenting its fleet with more electric shunting equipment, providing where possible to complete the electrification of the yards at an expense that would be offset by the service economies and longer service life of an electric shunting vehicle compared to a Diesel traction vehicle.^[47]

On the other hand, the TIBB also recalled in its analysis the considerations against convenience, such as the need to have a certain number of fully autonomous locomotives (Diesel) available for ready intervention in case of accidents affecting the power supply network or for its maintenance, as well as safety constraints that required a certain number of non-electrified tracks to be present on the yards.^[47]

For their part, the FS decided not to go beyond the planned orders and, in order to avoid the recurrence of accidents that dragged with them lengthy court cases, they later undertook the de-electrification of many of the yards' sidings.^[48]

In 1972, in a series of talks between representatives of the FS and the Institute of Automation of the Faculty of Engineering of the University of Rome "La Sapienza," it was agreed to experimentally transform a locomotive of the E.323 class by replacing the rotary converter and the DC traction motor with an electronic converter suitable for powering a three-phase traction motor.^[49]

This was an important experiment because it constituted the world's first application of a three-phase traction motor to a 3 kV DC locomotive, the main critical issues of which were related to the state of the art of power thyristors, which were then suitable for relatively low working voltages and were extremely sensitive to overvoltages, which in 3,000 V DC electrification systems could reach peak values of up to 12,000 V due to line inductance.^[50]

Although a shunting locomotive allowed only partial use of the advantages offered by the three-phase motor, the decision to carry out the experimentation on E.323s, which were equipped with a single motor of relatively low power that would make it possible to minimize the difficulties and expense of transformation, was considered a very convenient tradeoff.^[49]

The division of tasks called for the Institute of Automatics to carry out the feasibility study, choose the traction motor, design and build a laboratory prototype of the converter, and build the control circuits for the converter. On the other hand, the FS was responsible for purchasing the traction motor, making the final converter and auxiliary equipment, reassembling the locomotive, and financing the entire work.^[51]

It was also agreed to precede the assembly on the E.323 with an experimental application on the ground, carried out at the premises of the electrical substation in Rome Magliana by the State Railways Experimental Institute.^[50]

The conversion work initially involved only the replacement of the electrical traction equipment, but the subsequent choice of a 4-pole three-phase motor, more advantageous in terms of mass and footprint than the 6-pole motor initially planned, required the transmission ratio to be changed to compensate for its higher rotational speed.^[50]

The new traction equipment included:^[50]

• a filter with the dual purpose of protecting the electronic components from line surges and reducing the introduction of harmonics into the traction current to acceptable limits;
• a thyristor inverter to convert the 3 kV direct voltage to a three-phase alternating voltage with amplitude and frequency varying continuously from 0 to 2.4 kV and from 0.5 to 130 Hz;
• a control circuit, with automatic control, of the converter;
• a 4-pole, 3-phase asynchronous traction motor with a cage rotor and rated power of 280 kW (380 hp).

A constant tractive force capability, i.e., with power increasing linearly with speed, of about 79 kN (18,000 lbf) in the speed range between 0 and 13 km/h (0.0 and 8.1 mph) and with slightly decreasing power, from a maximum of about 276 kW (370 hp), from 13 km/h (8.1 mph) to maximum speed was planned for the new locomotive.^[52]

Electric braking was planned without in-line recovery, with energy dissipation on a resistor.^[53]

In 1973 funding was allocated by the FS and studies began, leading to the submission of the feasibility report in December 1974 with a favorable outcome.^[53]

By mid-1977, the progress of work was as follows:^[53]

• the construction of the laboratory prototype of the electronic converter had been successfully completed;
• the control circuit of the converter had already received substantial refinement;
• the premises of the Magliana electrical substation had been chosen, where the installation of the final electronic converter was imminent.

After the realization and ground testing by the FS Experimental Institute of the electronic equipment devised by the Institute of Automatics at the University of Rome, developments in power electronics related to the E.402 locomotive project caused interest in the E.323 inverter to wane, and the project was abandoned.^[54]

As was the case with E.322, the E.324 engine trailer was nicknamed "dog" or "doggie" because it appeared to be walking on the leash of its master, E.323.^[55]

On the subject of the historical data of any class of railroad rolling stock, two points in the introduction by engineer Fabio Cherubini, former manager of the FS Material and Traction Service and railroad popularizer, to one of his publications are noteworthy:

The greatest care has been taken to identify the builders and years of construction of individual units based on FS documents, but errors or imperfections of various origins cannot be ruled out. Even the builders' license plates^[56] do not give absolute certainty [...]

— Fabio Cherubini, Materiale, p. 7)

E.323 locomotives not suitable for remote control of E.324
Number of service	Admission in service[57]	Cancellation
E.323.001	1966	December 2002[58]
E.323.002	1966	December 2002[58]
E.323.003	1966	December 2002[58]
E.323.004	1966	after 30/1/2000[59]
E.323.005	1966	April 2004[60]
E.323.006	1966	October 2002[61]
E.323.007	1966	December 2002[58]
E.323.008	1966	December 2003[62]
E.323.009	1966	after 30/1/2000[59]
E.323.010	1966	after 30/1/2000[59]
E.323.011	1970	October 2002[61]
E.323.012	1970	December 2002[58]
E.323.013	1971	December 2002[58]
E.323.014	1971	October 2002[61]
E.323.015	1971	after 30/1/2000[59]
E.323.016	1971	October 2002[61]
E.323.017	1971	after 30/1/2000[59]
E.323.018	1971	October 2002[61]
E.323.019	1971	October 2002[61]
E.323.020	1971	May 2003[63]

E.323 locomotives suitable for remote control of E.324			E.324 locomotives assigned in pairs
Number of service	Admission in service[57]	Cancellation	Number of service	Admission in service[57]	Cancellation
E.323.101	1966	after 30/1/2000[59]	E.324.101	1966	February 2003[63]
E.323.102	1966	after 30/1/2000[59]	E.324.102	1966	after 30/1/2000[59]
E.323.103	1966	after 30/1/2000[59]	E.324.103	1966	after 30/1/2000[59]
E.323.104	1967	August 2003[64]	E.324.104	1967	after 30/1/2000[59]
E.323.105	1967	preserved as historic rolling stock[65]	E.324.105	1967	preserved as historic rolling stock[65]
E.323.201	1971	April 2009[66]	E.324.201	1971	April 2009[66]
E.323.202	1971	luglio 2003[67]	E.324.202	1971	August 2003[64]
E.323.203	1971	April 2009[66]	E.324.203	1971	June 2009[68]
E.323.204	1971	December 2003[62]	E.324.204	1971	October 2009[69]
E.323.205	1971	April 2004[60]	E.324.205	1971	March 2003[63]

• FS Class E.321
• List of Italian rolling stock

• Tomaso Zattoni; Giuseppe Maffei (February 1960). "Le locomotive elettriche di manovra a 3000 V c.c. Gr. 321 per la rete elettrificata delle F.S.". Ingegneria Ferroviaria. anno 15 (2): 105–110.
• Giancarlo Marzocchi (April 1962). "Locomotive elettriche da manovra Gr. E.321 delle Ferrovie dello Stato". Rassegna Tecnica TIBB. anno 23 (2): 25–32.
• Fernando Barenghi (1965). "Nuove locomotive elettriche da manovra per le Ferrovie dello Stato". Associazione Elettrotecnica ed Elettronica Italiana, Elettrotecnica ed elettronica nei trasporti terrestri. Rendiconti della LXVI Riunione annuale. Montecatini 1965. Vol. fasc. 2. Memorie. Milano: Associazione Elettrotecnica ed Elettronica Italiana. pp. 58/1–58/6.
• Ministero dei Trasporti e dell'Aviazione Civile – Ferrovie dello Stato (1970). Prefazione Generale all'Orario di Servizio (edizione 1963, ristampa 1970 aggiornata con O.S. nº 1/1965 – 14/1965 – 18/1965 – 26/1967 – 56/1967 – 87/1967 – 17/1968 - 34/1968 – 35/1968 - 43/1969 – 51/1969 – 65/1969 – 109/1969 – 16/1970 – 24/1970 – 38/1970 ed.). Roma: Ferrovie dello Stato.

• Erminio Mascherpa (July 1977). "Il motore trifase nel futuro della ferrovia (quinta parte)". Italmodel Ferrovie. anno 27 (206): 441–446.
• Renzo Marini (1983). "Le locomotive E.323–E.324". Le locomotive elettriche delle FS. Vol. collana Quaderni FS, nuova serie n. 3. Roma: Ufficio Relazioni Aziendali FS. pp. 85–87.
• Giovanni Cornolò; Claudio Pedrazzini (1983). Locomotive elettriche FS. Parma: Ermanno Albertelli. pp. 213–215.
• Giuseppe Sergi (November 1985). "Tra Scilla e Cariddi". Voies ferrées edizione italiana. anno 4 (24): 22–25. ISSN 0392-9817.
• Roberto Rolle (January 1986). "Le E.321-322, approfondimento a corredo dell'articolo "OGR Verona"". Voies ferrées edizione italiana. anno 5 (25): 11. ISSN 0392-9817.
• Angelo Nascimbene (January 1986). "Dove e quante". Voies ferrées edizione italiana. anno 5 (25): 92–93. ISSN 0392-9817.
• Giovanni Cornolò (1994). Locomotive elettriche FS. Parma: Ermanno Albertelli. pp. 291–293.
• David Haydock (1995). Italian Railways. Locomotives and multiple units. Sheffield: Platform 5. pp. 23–24.
• Ettore Caliri (January 1997). "Treni sulle navi". I Treni. anno 18 (178): 23–27. ISSN 0392-4602.
• Tiziano Croce (July 1997). "E 321 – E 323, manovre col "cane"". Tutto Treno. anno 10 (100): 48–53. ISSN 1124-4232.
• Stefano Patelli (May 2000). "Il comando multiplo nelle FS". Tutto Treno. anno 13 (131): 20–29. ISSN 1124-4232.
• Fabio Cherubini (2000). Materiale motore FS 2000. Salò: Editrice Trasporti su Rotaie. pp. 7, 12, 24–25, 52.
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• "Notizie e fotografie". Archived from the original on 26 April 2015. Retrieved 4 July 2010.
• "Le motrici FS elettriche da manovra: E.321, E.322, E.323, E.324". 7 October 2023. Retrieved 7 October 2023.