Create, SU problem

https://preview.redd.it/899e2vwo5f0g1.png?width=1920&format=png&auto=webp&s=e00cad16165b64f9e7ffea96f9adeae8b76c954a

https://preview.redd.it/fqch8a4q5f0g1.png?width=1920&format=png&auto=webp&s=1e30871603df5570bb44bef3ef2cbf5a4beadeea

Why do I only have that amount of su even when i have more in the boiler status? (all steam engine are aligned together and i used a encased chain drive at the top to connect to the stressometer)