Power for the Baltimore Light Rail System is a nominal 750VDC - Volts DC, or
Direct Current. I say nominal, because the voltage can swing anywhere from
under 700V, to over 1100V, depending on how many trains are in that particular
power section, and what each train is doing.
Trains when accelerating use a lot of current. The substations can
supply this power, but they can get help from the trains in the form of
regenerated voltage if there is one in that section, and it is braking.
When the trains are braking, the motors act as generators (more correctly,
alternators, like in your car), and if the line is receptive, output that
generated voltage onto the catenary. Being receptive means the voltage is
lower than higher (around 750-800V).
If we have two trains in a particular power section, and they are both
braking at the same time, usually only one of them will output their
regenerated power up onto the catenary. This is because the one will
be enough to raise the catenary voltage up towards 900-1000V, possibly even
more. The second car would sense that, and divert it's output into the onboard bleeder resistors
mounted on the rooftop. There is more on this operation in my technical section
Two adjacent power sections are insulated from each other by a device called
an IJ, and Insulated Joint. Each IJ has two "fingers" that allow an
LRV's pantograph to grab power from each adjoining power section briefly, so
that the car is not without power even for an instant. This also means
that the pantograph provides a path for the two power sections to be
connected for a brief moment, but given the resistances involved, the
voltage drop in one substation should be momentary, and current flow
shouldn't be too high for very long.
In case two adjacent power sections need to be more permanently joined, in
the event that one has to be out of service for some reason, there is a
switch that bridges the two sections at the insulated joint. The
hi-voltage switch is at the top of the pole, while the handle to activate it
is below. Examples of these items are shown in the next three photos:
the IJ, the power leads to the switch, and the whole set-up. Notice
here, just north of the Lowe's pocket track, that only one of the wires has an
Most of the substations of the Baltimore Light Rail System are of the 1 megawatt variety.
There are three substations that are 2 megawatts: at the North Avenue shops, at
the stadiums, and one at the Cromwell shops. The shops need a 2 megawatt
substation to power the cars when they are in the yard during the winter and
have their heaters are on.
Hunt Valley - Standard 1 Megawatt
Location: CM MN0/885 - Corner of Pepper Road and Schilling Road
Notice that this is an "original" installation (the substation is a dark
green), and the feed from the substation comes up inside the pole, instead
of using a separate conduit, as they used down in Texas. Texas here
does not refer to the state of Texas - Texas is a community between Timonium
and Cockeysville, and the fire station located there across from the Target,
is #17 and called the Texas station.
Texas - CM MN0/730
Here we have the power feed from the substation coming up the pole in a
separate conduit, instead of inside the pole, as it does at Hunt Valley.
Cromwell - (CM S2/480)
At Cromwell, there are two substations, one for the station and yard, and
one for the line heading north. There are four power feeds, and IJ's
all over the place.
I love trains, and I love signals. I am not an expert. My webpages reflect what I find on the topic of the page. This is something I have fun with while
trying to help others.
Please Note: Since the main focus of my two websites is railroad signals, the railfan guides are oriented towards the signal fan being able to locate them.
For those of you into the modeling aspect of our hobby, my
indexa page has a list of almost everything railroad oriented
I can think of to provide you with at least a few pictures to help you detail your pike.
If this is a railfan page, every effort has been made to make sure that the information contained on this map and in this railfan guide is correct. Once in a while,
an error may creep in :-)
My philosophy: Pictures and maps are worth a thousand words, especially for railfanning. Text descriptions only get you so far, especially if you get lost or
disoriented. Take along good maps.... a GPS is OK to get somewhere, but maps are still better if you get lost! I belong to AAA, which allows you to get
local maps for free when you visit the local branches. ADC puts out a nice series of county maps for the Washington DC area, but their state maps do not have the
railroads on them. If you can find em, I like the National Geographic map book of the U.S..... good, clear, and concise graphics, and they do a really good job
of showing you where tourist type attractions are, although they too lack the railroads. Other notes about specific areas will show up on that page if known.
Aerial shots were taken from either Google or Bing Maps as noted. Screen captures are made
with Snagit, a Techsmith product... a great tool if you have never used it!
By the way, floobydust is a term I picked up 30-40 years ago from a National Semiconductor data book, and means miscellaneous
and/or other stuff.
Pictures and additional information is always needed if anyone feels inclined to take 'em, send 'em, and share 'em, or if you have something to add or correct.... credit
is always given! Please be NICE!!! Contact info is here
Beware: If used as a source, ANYTHING from Wikipedia must be treated as being possibly inaccurate, wrong, or not true.