Junior Machine Learning Engineer

Overview

Trainline, Europe's leading independent rail platform, is hiring a Junior Machine Learning Engineer in London. The company's purpose is to empower greener travel choices, and its machine learning models support search and recommendations, pricing and routing optimisation, personalised experiences using reinforcement learning agents and generative AI, digital marketing systems and AI agents for customer support. The machine learning teams own the full delivery lifecycle from ideation to production.

The engineer joins an AI and ML platform team of engineers, scientists and product managers and works on large-scale production systems in an environment where learning and development are a priority.

What you will do

The role involves working in cross-functional teams, designing and delivering machine learning models at scale with measurable business impact, and owning the whole delivery lifecycle: data exploration, feature engineering, model selection and tuning, offline and online evaluation, deployment and maintenance. The engineer also helps design data-driven products with the team and stakeholders, builds tools, frameworks and libraries that speed up delivery, and takes part in the AI and ML community.

Requirements

Trainline asks for an advanced degree in computer science, mathematics or a similar quantitative discipline, proficiency in Python and open-source data libraries such as Pandas, NumPy and scikit-learn, and experience productionising models. Expertise in predictive modelling, classification, regression, optimisation or recommendation systems is required, as are Spark experience, knowledge of Docker, Terraform and MLOps platforms such as MLflow, experience with agile delivery and CI/CD, an understanding of data extraction and feature engineering, familiarity with statistics and good communication skills. Reinforcement learning, cloud infrastructure, large language model and graph or NLP experience are nice to have.

What you get

The salary range is 40,000 to 50,000 pounds. Benefits include private healthcare and dental insurance, a work from abroad policy of 28 days, a share purchase plan, an EV scheme, extra festive time off, family-friendly benefits, personal learning budgets and regular learning days. The hybrid model asks staff to work from the office at least 60 percent of their time over a 12-week period.

How to apply

The interview process has four steps: a 30-minute recruiter call, a 30-minute meeting with a Machine Learning Manager, a 90-minute technical interview with two engineers and a final interview with the Head of the team.