Complex sentence: About 1500 were made between 1919 and 1924 two of which are still retained by Siemens on the Lincoln site, one is fully restored in running/driving condition while the second example is still awaiting attention.
Split into simpler sentences: About 1500 were made between 1919 and 1924, two of which are still retained by Siemens on the Lincoln site. One is fully restored in running/driving condition, while the second example is still awaiting attention.