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Pushing the limits of BIM

Sir Peter Hendy

Network Rail has taken 4D building information modelling (BIM) further and longer than it has ever been before.

While BIM should be a familiar term to most, 4D is less well used. The introduction of the fourth dimension, time, into BIM, enables the various parties (consultants, contractors, clients) involved in a project to cycle through the various designs to see the construction timeline come to life. Mistakes can then be made in the office, rather than the work site.

4D BIM has been used once or twice on rail projects before, including Crossrail, and on a blockade at Walthamstow in east London on the Victoria Line last year. But those were projects at most 200m long, involving 2,000 lines on a Gantt chart, which displays activities (tasks and events) against time.

Sir Peter Hendy

Sir Peter Hendy

Network Rail chairman Sir Peter Hendy tries out the virtual reality technology, part of a 4D BIM program.

The Gospel Oak to Barking Line electrification project is a worksite 14 times as long, and with three times as many Gantt lines for the project management team.

Over 10 months the north London Overground line will get new overhead electric lines, while four sections of track will be lowered, four bridges rebuilt and a further six modernised. There are sections of slab track and ballast track, on a tight two-line corridor, using tiny clearances around Victorian infrastructure – all while reducing disturbance in high-density neighbourhoods.

To manage the Gospel Oak to Barking line’s complexity, Network Rail went for 4D BIM early on, opting for a single and simple piece of bespoke and interactive programming.

The company offering the software is Freeform, led by James Bowles and Liam Clarke, former employees of Bam Construction and Synchro respectively.

“A bit crazy”

Freeform has mainly worked mainly in construction, on smaller and more vertical projects. So Bowles calls the 20.8km aspect of this one “a bit crazy”.

“The challenge and opportunity at this scale – it was quite a broad task.”

The task begins with logging and digitising all elements of a project – plant, actions, manpower. Then by adjusting one element in a plan, the software instantly reveals the future implications for other elements, and any conflicts that might arise.


So can you experiment with the software settings and brainstorm solutions? “It’s not a mega-computer that solves problems on the spot,” says Network Rail project interface manager Brett Chatwin says. “But it’s the certainly the closest thing towards being able to do that.”

This full digitisation of the project cost about £120,000. But Chatwin says it has paid for itself many times over.

“The reason we went for a model rather than a paper-based exercise was that every time there was a change to the programme, you have to go from scratch and do the whole thing again. The model is much more flexible and has all of the links built in, so, if you move one thing,  you’re really moving about 10 to 15 [later in the plan].

“There were four or five instances where, if we didn’t use that modelling, we would have gone out and made mistakes. And you’re looking at £75,000 to £80,000, every time you lose a weekend’s work. And because of the nature of the business you can’t just start late. So pretty quickly it’s four to five hours lost and that’s a whole weekend lost.”

4D Screenshot

4D Screenshot

The software can provide a 3D representation of project management charts.

An unexpected, but welcome, bonus has come from the virtual reality function. Train drivers returning to work on the line will be re-introduced to the trains using virtual reality headsets. The drivers use the 3D model to get to know how the new line works (where the new signals are, how tight the corners) which saves two weeks of test runs after the project is complete.

But it is the start of the project where Network Rail and Freeform agree that digitisation has most benefit. In an ideal world, 4D BIM should happen as early as possible, they say, even at the project’s inception.

“To make the most of the technology, the building must be done virtually,” Bowles says. “That’s a massive reversal from creating an animation, and just saying ‘oh yeah, that works’.”

The software also changes the way people work, says Bowles.

4D Screenshot

4D Screenshot

In the software, train directions and movement are pictured alongside planning decisions.

“What we see a lot of at meetings is that instead of everyone in silos, everything is centralised, with everyone making the same decision at the same time, and that’s incredibly powerful.

“This is all done in a workshop environment, with six to seven people sitting around for a few hours, so we’re unlocking the expertise. This wasn’t an exercise that somebody in the corner is doing.”

So is software the secret to success? Or would it have gone just as smoothly, and cheaper, without the technology?

“There’s so many different factors involved that you’ll never be able to point to something and say ‘that’s the sole reason that that went successfully’,” Chatwin says.

“We built all this from scratch, there’s a lot of lessons learnt, that we can share in the business, or industry. We’ll know it all that much better the second time around.”

 One of the reasons we’re using [virtual reality] is sometimes space can feel abstract… It adds another level of site knowledge, confidence.

Freeform founder James Bowles

One item on the learning curve has been: what level of 3D detail does the project actually need? Freeform spent a lot of time working on how the various plant, including RRVs (Road Rail Vehicles), would look in 3D. Bowles suggests this effort could have been better spent elsewhere. But as Chatwin adds, with what the team knows now, next time around the total effort in creating the software could be halved and the value doubled.

Chatwin predicts that all future professionals will work this way, if only to move a large quantity of labour away from the track, and into the office, or even into offices at home. Bowles says 4D could have applications in disaster relief, the military and heavy industry but will eventually affect anything that involves people and physical processes.

4D Screenshot

4D Screenshot

Using different interfaces, multiple views of track, plant and overhead lines can be viewed at once, with potential areas of conflict illuminated.

“It’s about who’s doing it first and who accelerates that,” he says.

Freeform also assisted Network Rail’s communications to be able to take a quick reading on the “planned vs actual” work done and send it to internal and external stakeholders.

The next steps for BIM are in view – remote working, augmented reality and machine learning – but virtual reality is already here, although Freeform has only four of its clients using this product add-on.

It is hard to truly appreciate what benefits the virtual world might have for civil engineering until you try it for yourself. New Civil Engineer stepped inside the virtual worksite and took a tour in both 1-20 scale (“you feel like you’re Godzilla” Bowles says), and 1-1 scale.

“One of the reasons we’re using it is that sometimes space can feel abstract, and you’re not appreciating the reality. It adds another level of site knowledge, confidence,” says Bowles.

“The challenge for us now is how to advance this. In 18 months we could be looking back at this [virtual reality headset] as if it’s an 80’s brick mobile phone.”


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