UIC 612-0: Harmonized Driver Machine Interface (DMI) Requirements for Trains

On the night of 12 October 2015, a cross‑border regional EMU operating between Luxembourg and Trier (Germany) experienced a complete loss of traction power while climbing a 1.8 % gradient. The driver, a highly experienced operator with 18 years of service, had only transferred to this new Stadler FLIRT fleet three days earlier. In the previous Alstom Coradia trains he was accustomed to, the “traction cut‑off” reset procedure required pressing a hard‑key labelled “RESET” twice, then a softkey on the diagnostic screen. On the new FLIRT, the same procedure was buried under four different menu levels, accessed via a completely different sequence of softkeys labelled “MAINT” → “TCMS” → “FAULT” → “RESET”. The driver, unable to locate the reset function within the 90‑second window before the train’s batteries drained, declared a failure. The train blocked the single track line for 2 hours and 17 minutes, causing estimated delay costs of €112,000. The subsequent ERA investigation found no hardware fault – only a failure of harmonisation. The root cause was the absence of a common, system‑level specification for the Driver Machine Interface that would have standardised the reset procedure across all rolling stock. (Source: ERA, 2016)

That missing specification is UIC Leaflet 612‑0: Driver Machines Interfaces for EMU, DMU, Locomotives and Driving Coaches – Functional and System Requirements Associated with Harmonised Driver Machine Interface. First published on 1 June 2009 (English edition, 142 pages), this leaflet is the foundational document of the entire UIC 612‑0x series. It does not focus on a single display module (like 612‑02 for CCD or 612‑04 for TRD). Instead, it provides the system‑level functional requirements that apply to all driver interfaces – from the layout of the master controller to the logic of the softkey menu tree, from the colour coding of alarms to the behaviour of the Train Display Controller (TDC). (Source: UIC 612‑0, Foreword; Normadoc, 2025)

What is UIC Leaflet 612‑0?

UIC Leaflet 612‑0, titled “Driver Machines Interfaces for EMU, DMU, Locomotives and Driving Coaches – Functional and System Requirements Associated with Harmonised Driver Machine Interface” (also known as the “Harmonised DMI Functional Requirements Specification”), is the master technical standard published by the International Union of Railways (UIC) that defines the functional and system requirements for the entire Driver Machine Interface (DMI) on all cab‑equipped rail vehicles. It is the “Part 0” of the 612‑0x series, meaning it sits above the more detailed implementation leaflets (612‑01 general requirements, 612‑02 CCD, 612‑03 TDD, 612‑04 TRD, 612‑05 ETD). (Source: UIC 612‑0, Clause 1; Normadoc product page, 2025)

The leaflet, published in English on 1 June 2009 (French and German editions published later in 2009), is 142 pages long and remains current and in force. Its scope is exceptionally broad: it applies to the driver’s entire working environment in the cab of locomotives, electric multiple units (EMUs), diesel multiple units (DMUs) and driving coaches. It covers both system level requirements (e.g., how the DMI interacts with the train’s control and command systems, the Train Display Controller architecture, redundancy concepts) and functional requirements (e.g., definitions of global train states, access to safety‑critical functions, softkey labelling, priority handling and failure modes). (Source: UIC 612‑0, Clause 1; UIC 612‑0, Clause 4)

The leaflet is structured into 9 main clauses and 3 normative annexes. Clause 5 defines the global train operational states (“Park”, “Drive”, “Shunting”, “Idle”) and how the DMI behaves in each. Clause 6 defines the DMI functional requirements, including the arbitration between display modules, softkey labelling, priority handling and failure modes. Clause 7 covers the system architecture, including the mandatory Train Display Controller (TDC). The normative Annex A defines the standardised pictograms to be used on all DMIs (e.g., brake cylinder pressure, pantograph up/down, doors released). Annex B specifies the minimum set of hard‑keys that must be present on the driver’s desk, regardless of the DMI implementation. (Source: UIC 612‑0, Table of Contents; UIC 612‑0, Annex A, B)

How does UIC 612‑0 define global train operational states and their effect on the DMI?

One of the most critical contributions of UIC 612‑0 is the standardisation of global train operational states. Before this leaflet, each rolling stock manufacturer defined its own states (e.g., “Standby”, “Setup”, “Run”, “Shunt”, “Coast”), leading to confusion when drivers moved between fleets. The leaflet reduces these to exactly four states, each with a specific DMI behaviour:

(Source: UIC 612‑0, Clause 5.2, Tables 1‑4; ERA ERTMS 015560, Clause 4.2.1)

The leaflet also defines how the DMI must transition between these states. For example, when the train moves from “Idle” to “Drive”, any active TDD fault list or ETD timetable must be automatically minimised to a status bar icon, and the CCD must become full‑screen within 1 second. When the driver engages “Shunting” mode (via a dedicated keyswitch or softkey sequence), the DMI must hide all non‑essential timetable and radio information to reduce distraction. (Source: UIC 612‑0, Clause 5.3)

What are the DMI functional requirements for softkey menu structure and arbitration?

UIC 612‑0 mandates a centralised arbitration architecture using a Train Display Controller (TDC), which decides which display module’s content is shown on the shared physical screen(s). The leaflet defines three priority levels for messages and display requests:

(Source: UIC 612‑0, Clause 6.1; CLC/TR 50542‑1:2025, Clause 5.1; EN 16186‑3:2016, Clause 5.5.1)

Beyond prioritisation, the leaflet defines strict rules for the softkey menu tree depth. The driver must be able to access any of the four primary modules (CCD, TDD, TRD, ETD) from the home screen in ≤ 2 softkey presses. Any safety‑critical function (e.g., GSM‑R emergency call, ETCS “Train Data” entry) must be accessible in ≤ 3 presses from any screen. The leaflet also mandates a “Return to Home” softkey (labelled “HOME” or a standard house icon) that returns the DMI to the home screen within 500 ms, regardless of current menu depth. (Source: UIC 612‑0, Clause 6.2; UIC 612‑01, Clause 5.4)

Another key functional requirement is the automatic fallback to the TDD if the primary display unit (or the TDC) detects a failure. Clause 6.3 states that if the ETD (timetable) screen fails, the timetable application must automatically be routed to the TDD within 5 seconds. If the primary CCD (ETCS) display fails, the TDC must immediately switch to a secondary, physically independent ETCS DMI (mandated by ERA ERTMS 015560) and alert the driver via a dedicated hard‑wired warning lamp. (Source: UIC 612‑0, Clause 6.3; ERA ERTMS 015560, Clause 4.2.7)

Comparison Table: UIC 612‑0 vs. Pre‑standardisation “Organ‑Console” Cabs

The following table compares the system‑level characteristics of a pre‑2009 non‑harmonised driver’s desk (often called an “organ console” due to its disorganised layout) with a fully UIC 612‑0 compliant DMI implementation. The improvements in safety, training efficiency and maintainability are substantial.

(Source: UIC 612‑0, Clause 1; Siemens Mobility, 2023; Stadler Rail, 2022; ERA, 2016)