alternatehistory.com

So about a year ago I asked what was the earliest realistic date that the industrial revolution could start (link here if anyone's interested: https://www.alternatehistory.com/discussion/showthread.php?t=279080). Now I'm wondering about specific inventions, mainly as the title says the steam engine, telegraph and locomotive. Were these inventions (or more specifically the later two) only able to be created in the 19th century or could they have came about earlier?
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