Remove submission link

Updated participation details for challenge owners and participants.

Author: OebbJan

content/organization/participation.md

@@ -16,7 +16,9 @@ banner:
 
 You can participate, if you are an employee of ÖBB, SBB, DB or a member organisation of the OpenRail Association.  
 
-As a **challenge owner**, you can share your challenge with us via this [form](https://share.openrailassociation.org/apps/forms/s/j5T8b5XocATQj5Rik5rcN5mH) till March 19, 2026. If your challenge is selected for Hack4Rail, we look forward to your pitch live in Vienna. You will find out if your challenge is included by the end of March, at the latest. Exactly two challenge owners should be present at the event for each challenge. However, the submission may be made by multiple people. 
+As a **challenge owner**, you could share your challenge with us till March 19, 2026 - *submissions are no longer possible at this time!*. 
+
+If your challenge is selected for Hack4Rail, we look forward to your pitch live in Vienna. You will find out if your challenge is included by the end of March, at the latest. Exactly two challenge owners should be present at the event for each challenge. However, the submission may be made by multiple people. 
 
 As a **participant**, you actively contribute to the hackathon by forming a team with others and tackling a challenge together. Railway-specific knowledge is just as important as data, coding, or other IT skills. We will open the registration by announcing the participating challenges on April 01, 2026. 
 
@@ -31,4 +33,4 @@ If you want to get a feeling for what to expect at the Hack4Rail in Vienna, chec
 {{< youtube SmvpGrI1P9w >}}
 
 ### Dreiländerhack 2023 - Wien
-{{< youtube mCjkUJ-Zah4 >}}
+{{< youtube mCjkUJ-Zah4 >}}