Ansaldo MicroLok II

Solutions for MicroLok II interlocking systems

The Westermo Microlok® II gateway is available in our Lynx Ethernet device server switches and Wolverine Ethernet extenders. This functionality delivered by WeOS allows rail operators and system integrators to implement cost savings on interlocking and signalling projects as well as helping provide additional resilience to networks.

Microlok® II is a protocol developed by Hitachi Rail specifically used within rail interlocking solutions. The Westermo gateway converts data from the native serial format to a UDP (user datagram protocol) packet that can then be transmitted alongside other data on a trackside Ethernet network. Westermo Lynx and Wolverine also provide the networking infrastructure capability allowing the use of gigabit fibre optic inter-connections and also the ability to use existing twisted pair or telecoms cables as the data path.

Functionality is provided to allow up to 64 Microlok® address translations to be made and monitored. Legacy key-on/key-off support is provided as well as a unique hot/standby configuration to provide a resilient channel for hot standby controllers.

For the kinds of installation where Microlok® is used product reliability is critical to ensure maintenance costs are minimised and trains are not delayed. To provide the best solutions Westermo design all these products to have MTBF figures in excess of 500,000 hours (MIL-HDBK-217F (Gb) 25°C).

MicroLok II application concept


The need

On any railway system an interlocking system ensures that rail traffic can pass safely along a section of track.  The track is monitored for passing traffic and at crossing points; this information is then used to control signalling. Protocols like MicroLok® II from Hitachi Rail are used to transmit this critical data.
Microlok II is a serial protocol so when many device controllers are used the cabling requirement can be significant. Serial solutions are point to point so a cable break will always cause a network failure.

Any trackside installation must be reliable even though the environment is hostile to data communications equipment. EMC levels can be high as many trains are powered electrically, vibration caused by passing trains is significant and temperatures in trackside cabinets can vary considerably over a year.

Networking consideration

The Microlok II protocol is a serial protocol designed to transmit messages from one Microlok II controller to another however the specification does allow for it to be transported over a IP network.
By using a converter to encapsulate the serial data in UDP packets the protocol can be transported over an Ethernet network. Ethernet networks can off course run resiliently ensuring communication even in the event of a cable failure.

The solution

In WeOS we have a comprehensive Microlok II gateway solution that can handle up to 64 addresses. There is also support for Hot / Standby configuration using heartbeat signal, this provides a resilient channel when controllers are in hot standby.

The inbuilt I/O port can be configured as an alarm output when session timeout occur.
WeOS do not only support the Microlok II protocol, with the layer 3 solutions we you can also use dynamic routing and port based firewall solutions.

Westermo products are incredibly robust. 3:rd party type test according to trackside signaling standards IEC 62236-4:2008 & EN 50121-4:2006 are available on all Westermo units supporting Microlok II. Units will also operate from -40°C to +70°C.

John Pavlos

Sales, Westermo North America

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