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 Signalling and signalling control solutions Operational software Operational software Infrastructure support services and systems Infrastructure support services and systems Rolling stock maintenance solutions 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:  VAMPIRE website:

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

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 P 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 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 springsLeaf springs Hanger linksHanger links HornguidesHornguides  A few particular challenges Links hanging from leaf springsLinks hanging from leaf springs Static indeterminacyStatic indeterminacy Reciprocating massesReciprocating masses The Cartazzi truckThe 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 model  And several hundred lines of Fortran!

Determining the CG height

The complete ‘Tornado’ model

‘Tornado’ model validation- locomotive

‘Tornado’ model validation- tender

The P2 ‘as-built’ model

Next… the modified P2 model

Thanks to the A1 Steam Locomotive Trust

Questions…?