Passive and Active: Learning and Level Crossings
In railway signalling, one of the most problematic or challenging part is, subjectively, the level crossings. It is the part where the road meets the rail, where normal railway operation which is rigid and structured, meets the road operation that in some ways, very loose and has many variables. It’s an interface and interface always are challenging, but it is more challenging because the road or public users do not generally have an understanding of the railway operation.
Level crossings nomenclature or taxonomy is generally divided into passive and active. Passive means there is “no” action needed from the railway operation, while the active requires action from the railway operation, which is normally the operator. Passive cost less, but I think carries higher risk. Passive and active level crossings both requires a lot of consideration into design, like how the users (public) would do when they approach and use the crossings. These are the types of level crossings, according to its type.
Passive
- User worked crossing – where public user opens the gate by themselves
- Footpath crossing – where they might not even be a gate
- Open crossing – like footpath crossing, but for roads.
- Barrow crossing – in stations (at the end of platform)
- Trainman operated with barriers – the train passing through some mechanism, will activate the barrier. Train driver has to drive slowly. Still considered passive, because signaller needs to do nothing.
Active
- Manually control – local or remote (within 400m) or very remote (CCTV).
- Manually control barrier obstacle detector MCBOD – It’s not manual, it’s automatic and activated by (a) sensing device(s). Silly name
- Automatically controlled – which is triggered by the train. Signaller has to monitor (which lends its name to being active.
Confusing, isn’t it?
I’ve been reading, and listening to people talk about level crossings for years, and I still have a hard time understanding all the types, let alone their intricacies and details. But while writing this post, I learned a bit more as I had to go and read about them again on Wikipedia, which helps me a lot in my understanding. Hence the title: active learning, like active level crossing, requires a lot more effort, but the rewards are much greater. In a way, it helps to reduce the risk of failing exams. Ha!
Thank you for reading.