WELCOME to Freemium Subscription
exclusively by New In Signal...
ASK THE DOC | Monthly articles by Doc Frank Heibel
HIGH PERFORMANCE SIGNALLING | Doc Frank Heibel
Capacity for Metro Signalling
Disclaimer: Any individual or business decision you may make based on the content of this article is solely and fully your own responsibility, and you cannot under any circumstance hold me, my business, or the publisher of this newsletter responsible for any consequences of such decisions.
In last month’s article, I wrote about setting capacity targets for the High Performance Signalling technology you plan to introduce, CBTC or advanced varieties of ETCS.
For a quick recap, I differentiated between design capacity and operational capacity, the difference being the capacity margin. What I did not mention last time is that the higher the capacity margin the higher the reliability of your operations, in other words the punctuality of your train services. This supports my recommendation from the previous article that you should aim for the highest possible realistic capacity target for your railway and that the chosen technology supports.
For today’s discussion. it is important to define another technical term: headway. The headway is the time (not distance!) between two trains that follow each other on the same railway line. The headway is inverse to capacity. For a capacity of 30 trains per hour the average headway is two minutes, because two times thirty is 60 (minutes in one hour).
From this, it can be derived that headway is inversely proportional to capacity. That means if capacity goes up, headway needs to come down. You have a two-minute headway for 30 tph but a longer three-minute headway for lower 20 tph capacity.
The use of headway as a measure of time is critical to conveying my key point in today’s article. And that is the operational impact on the capacity of a railway. Specifically, the length of time that trains spend stopped in stations.
To read more about this article and to have full access to premium content SUBSCRIBE to Basic Subscription Plan or Premium Subscription Plan.
ASK THE DOC
High Performance Signalling
Monthly updates and articles by Doc Frank Heibel
HIGH PERFORMANCE SIGNALLING | Monthly Articles

Ask Doc Frank Heibel
Articles by Doc Frank Heibel
What is High Performance Signalling?
First of all, welcome dear reader to my column about “High Performance Signalling”. I hope you find these articles insightful and instructive and will do my best to give you premium “food for thought” as well as practical and applicable advice. Yet it is prudent to add this…
So what do I mean by High Performance Signalling? And why do I think that CBTC provides that more than ETCS or any other mainstream signalling technology?
I coined that term High Performance Signalling around 2016 because I thought, and still think, that the popular (at least here in Australia) term High Capacity Signalling…
ask the doc | doc frank heibel
Subscription Plans
Free
Subscribe Now for FREE
- Free registration
- Timely updates
- Free Handbook Download
- Access to Newsletter Issues
- Access to introduction sections
Basic
Monthly fee 9,99 CHF
- Free registration
- Timely updates
- Free Handbook Download
- Access to Newsletter Issues
- Free access to the paid articles
Premium
Monthly fee 12,99 CHF
- Free registration
- Timely updates
- Free Handbook Download
- Access to Newsletter Issues
- Access to introduction sections
- Free access to the live events with our top authors