Treno ad alta frequentazione

ALe 426/502 TAF
An FNM TAF in Milan Cadorna station
Type and origin Power type Electric Builder Ansaldobreda, ABB, Firema Build date 1996-2000 Total produced 100
Specifications Configuration: ​  • AAR Bo2+22+22+2Bo (EMU4) Gauge 1435 mm Length 103.970 mm Width 2.820 mm Height 4.300 mm Electric system/s 3000 V DC Current pickup(s) Pantograph Engine type Three phase asynchronous Transmission 20/101 Loco brake Oerlikon FV3E
Performance figures Power output 3640 kW Tractive effort 214 kN
Career First run 1997 Disposition In service

ALe 426/506 TAF (acronym of Treno ad Alta Frequentazione) is an Italian Electric Multiple Unit (EMU) used mainly on commuter regional trains.

Two different companies employ them: Trenitalia and Ferrovie Nord Milano (FNM).

Concept design has been made by Italian designer Pininfarina.

Recently some slightly modified version of the EMU have been purchased by Moroccan Railways,

Description

Each train is formed by fixed sections of four bi-level pieces: two motorized units (ALe 426/506) and two coaches between them (Le 736). Two sections can be coupled together, but by now it is not possible on Trenitalia units (on FNM ones is common practice).

The total capacity of the train is of 469 seated and 372 standing passengers.

Technique

ALe 426/506 employs asynchronous three-phase traction motors feed by the 3000 V DC catenary, which produce a characteristic sound while accelerating and dynamically braking.

Motors are mounted on one bogie per motorized unit, for a total of two motorized bogies per section.

This choice, however, has not proven too wise: first of all the power is very high in respect of the weight (3640 kW for 273 tons.), and the poor distribution of traction power along the train (only on the edges) induces poor performances in case of poor adhesion.

In fact TAFs are known for their frequent wheel slippage.