Senior Machine Learning Engineer

Salary: £65,000 - 105,000 per year Requirements: • We are looking for an advanced degree in Computer Science, Mathematics or a related quantitative discipline, or equivalent experience. • We are looking for considerable experience productionising machine learning models, with strength in an area such as predictive modelling, classification, regression, optimisation or recommendation systems. • We are looking for strong proficiency in Python and open-source data libraries such as Pandas, NumPy and Scikit-learn. • We are looking for a solid grounding in statistical methodologies, along with data extraction, manipulation and feature engineering techniques. • We are looking for experience with Spark, agile delivery methods and CI/CD practices. • We are looking for familiarity with DevOps and MLOps tools and practices, such as Docker, Terraform and MLFlow. • We are looking for confidence influencing and communicating with stakeholders across technical and non-technical teams. • Ideally, we have exposure to cloud infrastructure, NLP or large language models, graph technologies, or experience in the transport sector or with geographic information systems (GIS). Responsibilities: • We will work within cross-functional teams alongside data scientists, software engineers, data engineers and product managers. • We will design and deliver machine learning models at scale that create measurable impact for the business. • We will own the end-to-end machine learning delivery lifecycle, including data exploration, feature engineering, model selection and tuning, evaluation, deployment and maintenance. • We will shape technical direction for our area, making well-reasoned architectural and modelling decisions that stand up at scale. • We will partner with and influence stakeholders across the business to propose innovative data products that make the most of our extensive datasets and the latest algorithms. • We will build tools, frameworks and libraries that accelerate the delivery of ML products and improve team workflows. • We will provide technical mentorship and support the development of less experienced engineers, without formal people management responsibility. • We will take an active role in our AI and ML community, helping foster a culture of rigorous learning and experimentation. Technologies: • AI • CI/CD • Cloud • DevOps • Docker • GIS • Support • LESS • Machine Learning • MLflow • MLOps • Mobile • Python • Spark • Terraform • numpy • pandas • AI Agents • Fine-tuning • Marketing • RAG • Web More: We are Trainline, champions of rail and focused on building a greener, more sustainable future of travel. Our platform helps millions of travellers find and book the best value tickets across carriers, fares and journey options through our highly rated mobile app, website and B2B partner channels. We are now Europes number 1 downloaded rail app, with over 135 million monthly visits and 6.3 billion in annual ticket sales, working with 270+ rail and coach companies in over 40 countries. We are a FTSE 250 company with over 1,000 Trainliners from 50+ nationalities, based across London, Paris, Barcelona, Milan, Edinburgh and Madrid. This Senior Machine Learning Engineer role sits within our Machine Learning and AI Team, and we operate a hybrid model with a minimum office attendance of 60% of time over a 12-week period. We offer perks including private healthcare and dental insurance, a generous work from abroad policy, 2-for-1 share purchase plans, an EV Scheme, extra festive time off, family-friendly benefits, clear career paths, transparent pay bands, personal learning budgets and regular learning days. last updated 36 week of 2026