Hello,
someone here has posted a simulation Model of the NE555 (555bip.lib).
I used it for cascading two 555 for an individual Timer circuit.
Thank You for this Model !
Everything was fine but I had the feeling that the 555s output was unusually weak.
I have only very limited knowledge of simulation models but as the creator of this one used an include file for the transistor parameters and also delivered the internal circuit diagram as a KiCad schematic I was able to add a BC847A model to the include file and use it for transistors Q4, Q31 and Q32.
These three transistors (Discharge & Output) are conspiciously big on 555 dies.
This change without deeper knowledge 
actually works fine !
Maybe this is useful for other users ?