Barrie Akin: As for the use of "Westinghousian"....Westinghouse manufactured railway breaking and signalling equipment. The reference is almost certainly to the sound of the Westinghouse air pumps attached to some locomotives to operate the brakes.

Jansy Mello: It makes a lot of sense.

I connected “Westinghousian” to a fridge that “…will rumble and shudder and crackle and pound…” (1942, “The Refrigerator Awakes”) and this was actually a “tone-deaf” association of mine since, in the short-story, the stopping train “sighs”  (”Presently, the train stopped with a long-drawn Westinghousian sigh.”).

I had one other rumbling appliance in my mind  (a heating system in a basement), but (luckily, as I now see) I avoided it because I couldn’t find the exact reference as highlighted in Brian Boyd’s biography of VN.* 

In the meantime, I found a quote from “Pale Fire”:  “The heating system was a farce, depending as it did on registers in the floor wherefrom the tepid exhalations of a throbbing and groaning basement furnace were transmitted to the rooms with the faintness of a moribund's last breath.”

It’s hard to keep on track my readerly hallucinations concerning grammar, style and the converging sensorial inputs from VN’s writings. It’s never simply a matter of “words” and “structure”…

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* -  But is was already accessible in the VN-L archives, where I found again J.Friedman’s collaboration for the translation from the original text in Spanish: Cf. https://listserv.ucsb.edu/lsv-cgi-bin/wa?A2=nabokv-l;ce101d8.0812  “José Maria Guelbenzu on-line in "Babelia"(23-12-2006)wrote about  Brian Boyd's AY, now translated into Spanish as "Los años americanos",where he praised Boyd's rendering of Nabokov's qualms with calefaction in the house he rented again in 1948 & in which VN finished "Lolita"), and how Boyd showed their transformation, by metaphors, in VN's afterword to "Lolita." 'Let's go to an example: in 1948 a friend gets the Nabokovs a house; Nabokov warns the friend that he is perfectly useless in regard to managing private heating systems. In this house its author finishes the extremely celebrated Lolita; Boyd considers the text of the novel's epilogue:

“in the afterword to that book [Lolita] he casually turns central heating into poetry as he muses: “Every serious writer, I dare say, is aware of this or that published book of his as of a constant comforting presence. Its pilot light is steadily burning somewhere in the basement and a mere touch applied to one’s private thermostat instantly results in a quiet little explosion of familiar warmth.” [P.129]

The reader should notice the three lines (authorship, heating, circle of familiar gratitude) that flow together and fertilize each other in the image, as well as the way that Boyd uses the text to point out the way imagination fertilizes contact with an object to create an image.'