Dynamic modelling of steam
locomotives using VAMPIre®
Owen Evans, DeltaRail
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
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
Websites
 DeltaRail website:
www.deltarail.com
 VAMPIRE website:
www.vampire-dynamics.co.uk
Introduction to Owen Evans
 Career railway engineer
 Sponsored student with BREL
 Worked on bogie structures 1991-96
 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
Why model steam locomotives?
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
The Class P2
 The A1 Steam Locomotive Trust, builders of ‘Tornado’,
wish to build a new Class P2 2-8-2 locomotive
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 2-8-2 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
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
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
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
The Cartazzi truck
The Cartazzi truck
The Cartazzi truck
The Cartazzi truck
The Cartazzi truck
The Cartazzi truck
The Cartazzi truck
The Cartazzi truck model
 And several hundred lines of Fortran!
Determining the CG height
The complete ‘Tornado’ model
The complete ‘Tornado’ model
The complete ‘Tornado’ model
‘Tornado’ model validation- locomotive
‘Tornado’ model validation- tender
The P2 ‘as-built’ model
The P2 ‘as-built’ model
The P2 ‘as-built’ model
The P2 ‘as-built’ model
Next… the modified P2 model
Thanks to the A1 Steam Locomotive Trust
www.a1steam.com
Questions…?