OSRD Bug: Incomplete Train Paths In Space-Time Diagrams

Introduction: Unraveling the "Project Path Operational Point" Glitch in OSRD

Hey guys, let's dive into a bit of a head-scratcher that's been affecting some of our OpenRailAssociation enthusiasts using OSRD. We're talking about a pesky issue where the project path operational point isn't behaving as expected, leading to some rather confusing visualizations in the space-time diagram. Specifically, for a train route like the one from Paris to Avignon, instead of seeing a complete and seamless representation of the train's journey across the diagram, we're encountering a frustrating situation where only a partial segment is displayed. This isn't just a minor visual hiccup; it can have significant implications for how we understand, plan, and analyze train movements within these powerful railway simulation tools. Imagine trying to manage a complex railway network when your core visualization isn't showing the full picture – it's like only seeing half of a map! Our goal here is to break down this OSRD bug, understand why it's happening, what we expect to happen, and how we can all work together to get it fixed. This incomplete train path problem is crucial for accurate railway operations, so getting to the bottom of this is super important for anyone relying on OSRD for robust planning. We'll explore the specific example of the Paris to Avignon route, comparing the buggy display with the correct track projection to really highlight the discrepancy. We want to ensure that all train paths, every single one, are fully and accurately represented, providing reliable data for critical decision-making. This article will be your guide, whether you're a developer looking to contribute or a user trying to understand the issue better. Let's make sure our operational points are always spot on and giving us the full story. This deep dive will offer practical insights and a clear path forward, emphasizing the collaborative spirit of the OpenRailAssociation community.

The Curious Case of the Missing Space-Time Diagram Segment

Alright, so let's get into the nitty-gritty of what happened. We're seeing a really odd behavior with the project path operational point within OSRD. When you set up a train journey, for instance, a classic trip from Paris to Avignon, you'd naturally expect to see its entire trajectory plotted beautifully on the space-time diagram. This diagram is our visual bread and butter for understanding train movements over time and distance. However, in this particular bug, the diagram is showing something entirely different – and quite frankly, incomplete. The train path for our Paris to Avignon journey only occupies a fraction of the space-time diagram it should cover. Instead of a continuous, full line stretching from its origin (Paris) to its destination (Avignon) across the correct time window, we get a truncated segment. This visual glitch is not just annoying; it directly impacts the utility of the diagram for any serious railway planning. Imagine you're trying to identify potential conflicts, analyze delays, or optimize schedules, and your primary visual tool is only giving you half the story. You might wrongly assume a segment of track is free, or miscalculate arrival times because the visual representation is fundamentally flawed. This partial display creates significant blind spots and can lead to errors in operational planning. The problem lies with how the operational points – the data points that define a train's location at specific times – are being processed or rendered. It seems like the system is either failing to generate all necessary operational points for the entire route or is incorrectly truncating their visualization on the diagram. This inconsistency undermines the very purpose of a space-time diagram, which is to provide a comprehensive, at-a-glance overview of train movements. The consequence? A less reliable planning environment, more potential for manual oversight, and a general lack of trust in the system's output. For anyone involved in railway operations or capacity planning, an accurate and complete space-time diagram is non-negotiable. This bug, therefore, represents a critical challenge for OSRD users and developers alike. We need these paths to be whole, guys, so we can make informed decisions every single time.

What We Expected: A Full and Glorious Track Projection

Now, let's talk about what we should be seeing – the ideal scenario, the full and glorious track projection that we all rely on when using OSRD and similar OpenRailAssociation tools. What we expect, and what is absolutely crucial for effective railway planning and simulation, is a complete and uninterrupted representation of the train's journey across the entire space-time diagram. Think about it: when you map a train from Paris to Avignon, you want to see that path clearly extending from the moment it departs Paris all the way until it pulls into Avignon. Every segment, every station stop, every acceleration and deceleration should be visibly and accurately accounted for. This isn't just about pretty pictures; it's about data integrity and operational reliability. A proper track projection provides an immediate, intuitive understanding of the train's schedule, its speed profile along different sections of the track, and its precise location at any given time. This continuous path is fundamental for a multitude of tasks: from identifying potential conflicts with other trains, optimizing resource allocation like locomotives and crews, to performing detailed capacity analyses of railway lines. When the project path operational point functions correctly, the space-time diagram acts as a powerful analytical tool, allowing planners to spot bottlenecks, evaluate schedule robustness, and make data-driven decisions. The images provided clearly illustrate this contrast: one shows a fragmented, incomplete path, while the expected image depicts a beautifully rendered, full-length trajectory that accurately mirrors the train's journey. This expected behavior isn't just a nicety; it's a core requirement for a railway simulation platform. Without it, the insights gained from the space-time diagram are compromised, leading to potential misjudgments in real-world scenarios. We expect OSRD to deliver a visualization that is as precise and comprehensive as the underlying data it manages. The full projection gives confidence, clarity, and empowers users to leverage the full potential of advanced railway planning. Anything less than this complete, accurate display of train movements leaves us guessing, which is definitely not ideal in the high-stakes world of railway operations. Getting back to this expected functionality is paramount for the continued success and reliability of the OpenRailAssociation initiatives.

Reproducing the Bug: A Step-by-Step Guide for Fellow Rail Enthusiasts

Okay, guys, if you want to see this project path operational point glitch in action for yourselves, we've got a super clear, step-by-step guide to help you reproduce it. Reproducing a bug consistently is half the battle won, as it provides invaluable information for developers trying to track down the root cause. This isn't just about complaining; it's about actively contributing to the solution! Here’s how you can replicate the incomplete train path issue for the Paris to Avignon route within OSRD: First off, you'll need the specific timetable that seems to trigger this behavior. You can grab it right here: [timetable.json](https://github.com/user-attachments/files/23963845/lol.json). Download this JSON file to your local machine. This file contains the precise scheduling data for the train movement from Paris to Avignon that exhibits the problematic visualization. Once you have the timetable.json file, you need to import it into your OSRD instance. The exact steps might vary slightly depending on your specific OSRD setup, but generally, you would navigate to the appropriate section within the OSRD interface (often a