The series is based on the novel series by Makoto Sanda with artwork by Mineji Sakamoto which began in 2014.
The series will go by Lord El-Melloi II-sei no Jikenbo: Rail Traveling Grace Note and now the official site has updated with a premiere date of July 6th, 2019.
It has eight volumes out as of this writing and a manga by Tou Azuma that began in 2017.