BCS Design Ltd

Structural Analysis of Cantilever Masts on the West Coast Main Line

Analysis of Cantilever Masts

The West Coast Main Line, the UK’s most important intercity rail passenger route, faces the challenge of an ever-increasing number of train journeys and the introduction of faster services. To meet these demands, an Autotransformer (AT) arrangement will be installed to provide a more robust power supply.

BCS Design were tasked with the design of a strengthening arrangement for the masts to accommodate the new power supply. Wilde Analysis engineers carried out a range of stress, buckling and other analyses to ensure that the masts conform to requirements.


The West Coast Main Line (WCML) is the most important intercity rail passenger route in the UK, handling millions of passenger journeys each year. With the continual increase of trains running on the West Coast Main Line (WCML) and the introduction of faster services between major stations, the current Overhead Line Equipment is quickly approaching its maximum electrical load capacity.

In order to continue providing a safe and reliable railway capable of meeting the increased demand, the system needs to be updated. The chosen solution is an Autotransformer (AT) arrangement. This type of arrangement has been successfully installed on other networks and operated in the UK and throughout Europe with great success. It will provide a robust electrical supply on the WCML that will meet today’s requirements and accommodate future capacity increases.

Fig. 1: Autotransformer (Courtesy: BCS Design Ltd)


The Autotransformer arrangement requires the installation of an extra wire, creating higher loading implications. The effect of additional loads due to dead weight, wind, and ice build-up on the additional wire needed to be investigated.

Another issue is that the cantilever masts used to support the existing overhead power lines were designed to a previous standard, and in some instances required modification to conform to the latest standards and requirements. BCS Design asked Wilde Analysis to look at a number of strengthening arrangements to allow the masts to support the additional wire, and to ensure that they satisfy modern requirements.

An important consideration for any proposed design solution was the ease with which it could be installed, given that the work must be carried out in situ along the track. This imposed limits on weight and height of the strengthening members from a health and safety perspective. Cost was another important aspect of the proposed solutions. This was not simply in terms of making the necessary components, but also the time it would take to install them across the large network of masts.

Fig. 2: Cantilever Mast (Courtesy: BCS Design Ltd)
Fig. 3: Cantilever Mast – Bracing (Courtesy: BCS Design Ltd)


The masts were subjected to four different load cases and assessed against stress, deflection and buckling criteria using ANSYS software. Through the FEA analysis, Wilde engineers were able to confirm that the additional strengthening allowed the mast to meet all allowable performance criteria.

Business Benefits

The analysis carried out by Wilde provided BCS Design with accurate measurable data to design safe and reliable components that conform to the latest standards and requirements.

This was a unique project for the client and for us. We required Wilde’s help and are very happy with the outcome. Wilde’s engineers also provided us knowledgeable advice and recommendations to improve our design work; there have been no issues with the fabrication and installation and we have found Wilde’s engineers very helpful throughout our design development and the client’s approval process.

BCS Design Ltd

About BCS Design Ltd

BCS Design Ltd provides a wide range of civil, structural, geotechnical and multi-disciplinary design solutions to the Rail, Highways and Civil/Structural Engineering sectors.

The scope of their work extends from Rail projects to Highways and from Temporary works to CDM co-ordination. As part of Capita plc, they are linked with more than 4,000 experts in 40 offices across the UK.



Ansys Mechanical is a finite element analysis (FEA) software used to perform structural analysis using advanced solver options, including linear dynamics, nonlinearities, thermal analysis, materials, composites, hydrodynamic, explicit, and more.

Read More

Axis Communications

Read more

Electrolux Professional

Read more


Read more

Hilite International

Read more

JBT Foodtech

Read more

Talk to us

Digital transformation is everything. Get it right! Talk to us. Our team is on hand to answer your questions.

Get in touch