Help with understanding electrical and pneumatic schematics for rolling stock

[Tech Warrior]

Hi All,

This is my first post, and I hope this is in the correct section. Recently, I have been involved with rolling stock systems but havn't examined schematic diagrams before to perform any fault finding diagnosis in both pneumatic and electrical schematics.

I have done my best looking for tutorials and information online for the type of schematic diagrams such as traction circuits, brake systems, power circuits but haven't found anything helpful. What I'm looking for are some resources that go through examples of pneumatic and electrical circuits and explaining how the functionality of components like inductors, circuit breakers, isolation cocks, relays, chokes and diodes can be used to analyse an issue with the system.

Would anyone involved in systems engineering or systems maintenance be able to recommend some resources I could access to learn about this or have any examples that you could post to learn from? I would be extremely grateful for any help in this area because it's something I really want to learn and become proficient with.

Than you.

 

[Nym]

Do you not have some kind of mentor at your workplace you could speak to about helping understand these things?

May I ask what your background is before you got into needing to use schematics?

Finally, it would help if I knew what standard of schematics you're working to.

Eg. Bombardier Switzerland power system drawings are very different to AdTranz and are very different to LUL drawings...

 

[Tech Warrior]

Hi Nym,

My background is Mechanical Engineering focussed on rolling stock. I have been involved with writing documentation, mod procedures, manuals examining vehicle failures and developing FMECA matrices. I do have some understanding of Electrical Engineering as well.

I don't have a mentor who can guide me through fault finding schematics but I reasonably good at picking things ups once I have a few simple examples where basic principles are applied.

The type of vehicles I may be examining would be Siemens Class 180/4 or vehicles run by First Capital Connect. At this stage it would probably be better to focus on simple electrical and pneumatic schematic drawings such as those used on LUL or metro vehicles e.g. 96 or 95 Tube Stock.

I hope that helps, and I appreciate any advice you could offer in this respect.

Thank you

 

[Nym]

I'd say it's worth looking down at the IMechE Library online resources for examples of drawings to look through. Accident reports might also be a reasonable start, the problem is that most issues that cause accidents are mechanical, not electrical problems...

I wouldn't call 95TS or 96TS particularly simple though...

I had a similar issue before when a group of mechanical engineers where trying to work around pneumatic schematics for a project with no electrical or pneumatic engineers on it. In the end I had to walk them through it step by step to help them understand the fundamentals before understanding how the system would work. (Mechanical engineers at my place don't tend to understand pneumatics, they tend to focus on structures at university nowadays).

If you can try to understand...

- The function of each component at a system level, be it a large or small one, anything from a diode (depends on if it's a +ve or -ve earth!) to a MITRAC / MVB interface, everything can be abstracted to essentially a truth table or table of variables for it's behaviour.

- How the connecting lines work

- The limitations of this understanding, and what you'd need to do to take it further, this would only really help with system level understanding, not things like current carrying capability or parasitic components.

Then you should be able to be on the way to understanding the schematics.

Most of the time when I'm trying to teach graduates and apprentices how to understand these, it's a lot of one on one tutoring in person, unfortunately that doesn't work via an internet forum.