Tenses

1. having the railway company preannounced it to the public. (?)
2. the railway company having pronounced it to the public (?)
3. the railway company previously announcing it to the public (?).

Thank you so much for your thorough reply, dear bernice.farrugia but I still have concerns:

1.

bernice.farrugia

2. At dawn however railwaymen, breaking their promise, stop work without … - I would keep it simple and simple say 'At dawn, however, railwaymen, breaking their promise, stop work without informing the public'.  Do not forget that the first part of the sentence already includes a complicated sentence structure, so it makes more sence to simplify the structure of the second part of the sentence.

2. Yeah. The railway company announced the beginning of the strike, as promised (as it had been promised?)... - The correct answer is...as it had promised.  The subject of your sentence is THE RAILWAY COMPANY.  Since you already have a subject you DO NOT NEED TO CHANGE YOUR SENTENCE FROM ACTIVE TO PASSIVE.  IT refers to THE RAILWAY COMPANY and it should be followed by an ACTIVE verb -had promised. - I am still not convinced that it cannot refer back to the promise itself and not to the company. Athough I am glad to see that you also prefer the Pluperfect.

 Any other suggestions? 

Thanks again, bernice.farrugia!

Thanks Bernice. Now I see your point.

One last thing: Do you think the following is correct:

At dawn however railwaymen, breaking their promise, stop work without having the railway company preannounced it to the public.

(Other) natives do not agree. Some say that ...

It refers to the matter being discussed, i.e. railwaymen stop work. The structure is conversational. A more formal structure would be: At dawn, however, railwaymen, breaking their promise, stop work without having the railway company preannounce that they would do so.