1. Dynamic modelling of steam locomotives using VAMPIre®
Owen Evans, DeltaRail

2. Introduction to DeltaRail
We are a software and technology products and services business with offices in Derby and London
We were formerly AEA Technology Rail and BR Research
We provide:
Signalling and signalling control solutions
Operational software
Infrastructure support services and systems
Rolling stock maintenance solutions
One of our products is VAMPIRE®, a well-proven computer package for modelling the dynamic behaviour of railway vehicles

3. Introduction to VAMPIRE®
VAMPIRE® was developed during the APT project to simulate the behaviour of high speed rail vehicles
It has been developed and expanded into a reliable and easy-to-use tool for railway vehicle dynamics engineers
It is currently licensed to customers all over the world
It has very rarely been used to model steam locomotives

4. Websites DeltaRail website: VAMPIRE website: www.deltarail.com

5. Introduction to Owen Evans
Career railway engineer
Sponsored student with BREL
Worked on bogie structures
Carried out dynamics for the new Turbostar and Electrostar trains using VAMPIRE®
Left Adtranz and joined AEA Technology in 2001
Can’t remember a time when I didn’t love steam locomotives

6. Why model steam locomotives?

7. Background
Most current new builds are largely replicas of successful prototypes, some incorporating existing parts
Vehicle acceptance on basis of ‘grandfather rights’
This approach is less favoured now
Some groups may wish to modify existing locomotives to improve performance
Some may wish to build a new design of loco using modern technology
Some may wish to build new locos based on old designs that were not entirely successful and will need to change the design

8. The Class P2
The A1 Steam Locomotive Trust, builders of ‘Tornado’, wish to build a new Class P locomotive

9. The Class P2
The original locos were fast and powerful and a new one would be able to pull heavy trains on Network Rail
The new loco as the only full size in Britain would attract great interest
The originals were accused of causing track damage and suffered from broken crank axles
The new version will have to be significantly modified
The modern approvals process will require such a loco to be modelled dynamically
Before this a feasibility study is required, involving dynamic modelling

10. The Class P2 feasibility study
New area for VAMPIRE, so important to have a validated model
Test results available for ‘Tornado’ track tests on GCR and Newcastle-York
VAMPIRE model of ‘Tornado’ created and validated
Model modified to represent Class P2 as built
Aim to reproduce curving problems found in practice
Apply proposed design changes (mainly pony truck) and assess effectiveness
Help to decide whether to proceed with project

11. Challenges of steam loco modelling
Much of suspension similar to older freight vehicles
Leaf springs
Hanger links
Hornguides
A few particular challenges
Links hanging from leaf springs
Static indeterminacy
Reciprocating masses
The Cartazzi truck

12. Reciprocating masses
Calculate and apply sinusoidal forces using User Subroutine
Frequency can be derived from speed
Need to calculate longitudinal and vertical forces and roll, pitch and yaw moments on loco body and wheelsets

13. The Cartazzi truck

14. The Cartazzi truck

15. The Cartazzi truck

16. The Cartazzi truck

17. The Cartazzi truck

18. The Cartazzi truck

19. The Cartazzi truck

20. The Cartazzi truck model
And several hundred lines of Fortran!

21. Determining the CG height

22. The complete ‘Tornado’ model

23. The complete ‘Tornado’ model

24. The complete ‘Tornado’ model

25. ‘Tornado’ model validation- locomotive

26. ‘Tornado’ model validation- tender

27. The P2 ‘as-built’ model

28. The P2 ‘as-built’ model

29. The P2 ‘as-built’ model

30. The P2 ‘as-built’ model

31. Next… the modified P2 model

32. Thanks to the A1 Steam Locomotive Trust

33. Questions…?