"Mangos" is just a short name for "vías de mango" as used here:

http://www.spaintrainzrutas.com/docu/RPGuijuelo.pdf
http://www.tunnelbuilder.es/headline_1308_2.htm
http://www.metrodemalaga.info/index.php?id=33&tx_ttnews[tt_n...



"Vías de mango", as you can see in this reference:

http://prensa.adif.es/ade/u08/GAP/Prensa.nsf/dicciona.htm

has several slightly different meanings in spanish. In general is used to refer to a dead-end siding used for storing, parking or sorting rolling material.

You will find the term "shunting neck"/"headshunt" as translation of "vías de mango" to english, but, IMO, these terms only cover a specific type of "mango", which is not the type being referred to in your text.

http://www.proz.com/kudoz/spanish_to_english/engineering_gen...
http://books.google.es/books?id=et6IRQ60RO0C&pg=PA457&lpg=PA...

See definition for shunting neck/headshunt here:

http://en.wikipedia.org/wiki/Glossary_of_rail_terminology

I do not believe this is the case, since the text clearly states that these "mangos" are tracks for parking specifically, but, in any case, you could use it if you have any other context that points in that direction.

I would use "dead-end sidings" or, even, "parking spurs", in the sense defined here:

http://www.railcarmover.com/glossary.asp

and used here:

http://www.spikesys.com/EBT/News/mucrr.html


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Note added at 1 day22 hrs (2010-10-30 08:23:08 GMT) Post-grading
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You are very welcome, Edward