Shunt enhancement - success?

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TSS
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Shunt enhancement - success?

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It’s been approximately 10 months since the first tests of the “shunt enhancement” devices occurred in August 2023 in Illinois, continuing at the Pontiac yard and on the Holly Sub.

I can’t say that I’ve seen any concrete news regarding success or failure, but I guess it was successful, as MDOT wrote the following in an update provided to the Michigan Association of Railroad Passengers:

The CRISI Notice of Funding Opportunity closes on 5/28/24, and MDOT’s pending applications
include the Michigan Line Bridge Reconstruction Project (to construct 5 bridges).

MDOT is also supporting three Amtrak applications:
▪ Final design of a double tracking between Niles and Glenwood Road
▪ Feasibility analysis to connect Pere Marquette to the Amtrak-owned corridor in
New Buffalo
▪ Shunt enhancement for Charger locomotives

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Re: Shunt enhancement - success?

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Boy, they just will NOT let go of that idiotic connection between the CSX and the MI Line. How much time would that really save, 3 minutes?
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Re: Shunt enhancement - success?

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SD80MAC wrote:
Mon May 20, 2024 1:57 pm
Boy, they just will NOT let go of that idiotic connection between the CSX and the MI Line. How much time would that really save, 3 minutes?
I don’t get it either. I can’t see the benefit for the millions in expense. If they want to reduce transit time, it would be far cheaper (and money well spent in my opinion) to re-time the crossings and increase the speed limit through Michigan City. Maybe add a distant signal at St. Joe and Bangor as well. Then call it good.

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Re: Shunt enhancement - success?

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SD80MAC wrote:
Mon May 20, 2024 1:57 pm
Boy, they just will NOT let go of that idiotic connection between the CSX and the MI Line. How much time would that really save, 3 minutes?
Cuz new station in NB...lol
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Re: Shunt enhancement - success?

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SD80MAC wrote:
Mon May 20, 2024 1:57 pm
Boy, they just will NOT let go of that idiotic connection between the CSX and the MI Line. How much time would that really save, 3 minutes?
And be an engineering nightmare to try and tie-in a high-speed turnout in the curve the AML is on there.

Dumb.
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Re: Shunt enhancement - success?

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Excuse me, but what is "shunt enhancement"?

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Re: Shunt enhancement - success?

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MiddleMI wrote:
Tue May 21, 2024 2:34 am
Excuse me, but what is "shunt enhancement"?
I am not a signal guy, so my definition is probably crude, so bear with me. Shunt is basically the act of a locomotive and or rail car completing (shunting) the circuit in a section of signaled track to show occupancy. Signal systems are divided more or less into blocks or varying lengths, depending on the territory. When there is no train in a block, the block will show as "clear". When a train enters the block, the wheels and axles bridge the "gap" between the 2 rails, completing the circuit and showing that the block is occupied. The act of the wheels and axles completing the circuit is called shunting.

Why is this important? Well, if a train loses shunt or shunts intermittently, that can create lots of problems for the signaling system! Lineside signals, crossing protection, every warning device relies on block occupancy and shunt to function properly. Passenger equipment is, on average, much lighter than freight equipment, and can lose shunt more easily. This is why railroads like CN and CSX have imposed minimum axle counts in passenger trains (usually 20 axles or more), because they were having issues with passenger trains failing to shunt signals and or crossing protection. This is also the reason why railroads usually limit single lite engine moves to 30 mph or less, as a single locomotive moving faster than that can run the risk of losing shunt. I've actually seen that happen with single locomotives running lite in an approach-lit signal block. The locomotive lost shunt and the signal actually shut off for a few seconds before flicking back on!

Rusty rail conditions also hamper shunt, especially with lighter weight trains. Amtrak and Penn Central ran into this problem in the 70s on the Michigan Line. The Turboliners that Amtrak was using in Detroit-Chicago service were so light that they weren't knocking all of the rust off the rail heads, and the trains were losing shunt often. PC's solution was to detour a few weekly freight trains (rust breakers) that usually took the Air Line, via the MC through Kalamazoo to ensure the rails were rust-free.

I'm not entirely sure how these shunt enhancement devices work, but the goal is for the locomotives and cars to have reliable, full-time shunt so Amtrak doesn't have to unnecessarily run more cars on a train than necessary, while also ensuring 100% functionality for signals and crossing protection.
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Re: Shunt enhancement - success?

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TY for the information. It’s not what I thought it would be so this is helpful.
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Re: Shunt enhancement - success?

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SD80MAC wrote:
Mon May 20, 2024 1:57 pm
Boy, they just will NOT let go of that idiotic connection between the CSX and the MI Line. How much time would that really save, 3 minutes?
The question may be who is pushing for that connection. Is it Amtrak, MDOT, or the local community. The only advantages I could see with the connection to the CSX line would be 1) allowing a connection between traffic going from Grand Rapids / Holland to points east like Ann Arbor and Detroit. Currently the Pere Marquette trains don't stop in New Buffalo, so if they switched to the Amtrak line, passengers could then switch from the PEre Marquette to Wolverine trains in New Buffalo (with the hour or so delay). 2) remove a connection in Indiana that Amtrak would need to traverse?

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Re: Shunt enhancement - success?

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chapmaja wrote:
Tue May 21, 2024 12:26 pm
The question may be who is pushing for that connection. Is it Amtrak, MDOT, or the local community.
Taxpayers. Probably Federal funds similar to all the other projects Amtrak wants funded from programs available to other railroads.

chapmaja wrote:
Tue May 21, 2024 12:26 pm
The only advantages I could see with the connection to the CSX line would be 1) allowing a connection between traffic going from Grand Rapids / Holland to points east like Ann Arbor and Detroit. Currently the Pere Marquette trains don't stop in New Buffalo, so if they switched to the Amtrak line, passengers could then switch from the PEre Marquette to Wolverine trains in New Buffalo (with the hour or so delay). 2) remove a connection in Indiana that Amtrak would need to traverse?
A train to train transfer at New Buffalo would be interesting but I doubt it would be heavily used. It seems to be a long way to go south just to head east. I believe there is/was a bus route that does that. If that bus is still active it could provide some ridership numbers. (Bus from GRR to KZO would be a shorter route.)

The CSX connection in Indiana starts at the same CP where Amtrak leaves the NS line ... literally two tracks to the northeast from Porter. It would provide a few miles of faster track.

While we are dreaming, how about have Amtrak purchase the CSX line from Porter to New Buffalo and upgrade it to 110 MPH? Then Amtrak would have a faster route through Michigan City with no conflict with the NICTD South Shore or the drawbridge. NS could purchase and run the Michigan Line if they wanted to serve freight customers or let CSS take over the freight service from Burns Harbor to New Buffalo similar to CSS taking over the CN City Line in Gary.

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Re: Shunt enhancement - success?

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Saturnalia wrote:
Mon May 20, 2024 9:25 pm
SD80MAC wrote:
Mon May 20, 2024 1:57 pm
Boy, they just will NOT let go of that idiotic connection between the CSX and the MI Line. How much time would that really save, 3 minutes?
And be an engineering nightmare to try and tie-in a high-speed turnout in the curve the AML is on there.

Dumb.
Why does it need to be a high speed turnout in the curve?? There is plenty of room to run the connection track down to the west where the track would be straight....and seeing how the curvature of the connecting track between the two isn't gonna preclude a high speed operation, a medium speed turnout and curve btw the two will do just fine (what's the speed of CSX at that location anyways??).

Pretty sure MDOT is looking at the potential of higher psgr. loadings at the NBU station for the people who live there and commute to CHI....a NBU stop for the Pere Marquette would get psgrs. there almost 2.5 hrs faster than the first westbound train that stops there (365), as the first westbound train (351) blows thru town at 95 mph without stopping.

What the tax payers should be annoyed with is the expenditure of funds to put in double track btw Glenwood and Niles. This section has 3 sidings within a 18 mile distance ( CP-172 is the west end of Glenwood siding and CP-190 is the east end of the Niles siding with the Dowagiac siding in between from CP-180 to CP 182. This section of the Michigan line has ONE scheduled meet ( 350 and 365) between the 8 trains that run this section--that Amscam claims is congested now....so MDOT will be on the hook to put in 16 miles of new track that really isn't needed ---unless there is a great influx of new trains running on the Michigan Line

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Re: Shunt enhancement - success?

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yet Michigan Line east has about 21 miles of single track between Ypsi and Chelsea but with only 352/355 scheduled to meet. Save the money , scrap the siding, use it for more useful things :)

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Re: Shunt enhancement - success?

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MiddleMI wrote:
Tue May 21, 2024 2:34 am
Excuse me, but what is "shunt enhancement"?
SD80MAC's explanation for "shunting" is close, actually, it's the opposite in theory. "Shunting" for the railroad crossings & signal systems is the train shorting out the energy that travels down the rails. The typical track circuit for the signal system has a low DC voltage applied the rails, negative on one rail & positive applied to the opposite rail at one end of the signal block that flows down the rails to the opposite end of the signal block with a wire attached to each rail going into the signal hut to energize the coil of a Track Relay.

The Track Relay's coil is energized by the DC voltage from the rails when the signal block is clear of any trains. When a train enters the signal block, it shorts out the track circuit voltage & the Track Relay will de-energize. It's a "fail safe" design that will show the track circuit as being occupied by a train should their be a broken rail or broken track wire or any other type failure that would either reduce or kill the track circuit's voltage. We have had incidents where a mouse had chewed thru the track wire insulation inside the signal hut that ended up stopping a train.

Some railroad crossings will use a DC voltage placed onto the rails or an AC voltage transmitted on the rails ranging from 470Hz & above. With crossings that may be close to one another, different frequencies are used for each crossing & it gets shunted (shorted out) by the train's wheels/axles to trigger the crossing.

I had once maintained FSO (Frequency Shift Overlay) devices that protected sidings having hand throw switches that would prevent vandals from cutting off the lock & waiting for a train to get close & then throw the switch to divert the train. With the FSO system, the train had to be within 75 feet of the switch to allow an unlock. The FSO was a transceiver, where, one rail was the "transmitter" & the other rail was the "receiver". For this equipment, the train shunting completed the path from one rail to the other.

The more modern solid state signal equipment transmits digital pulses on the rails to track trains with each signal location "talking" back & forth between each other & they rely on the trains properly shunting the track, as well.

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Re: Shunt enhancement - success?

Unread post by SD80MAC »

Thanks, Tom. You’re right, shorting/interrupting the circuit is a better definition.
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Re: Shunt enhancement - success?

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I realize this is going back to railroading 101, but for the less technically inclined such as myself, I was able to find some diagrams to show this. I believe the train is traveling "down" on these diagrams:

Image

And this is the situation with the WTAMA:

Image

Still curious if anyone knows what Amtramk's "enhacenments" are exactly, and still a bit curious how something as heavy as a train of any size might miss shorting the track signalling circuit.

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Re: Shunt enhancement - success?

Unread post by SD80MAC »

You have to remember, the point of contact between a train’s wheel and the head of the rail is only about the size of a dime. Not a lot of contact when you think about it, especially on something as short as a passenger train.
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Re: Shunt enhancement - success?

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MiddleMI wrote:
Sun May 26, 2024 2:28 am
Still curious if anyone knows what Amtramk's "enhacenments" are exactly, and still a bit curious how something as heavy as a train of any size might miss shorting the track signalling circuit.
I believe it is an antenna that emits radio frequency energy that induces current into the rail.

Railway Age quoted an FRA waiver of compliance that said:

FRA says it understands the proposed shunt enhancer antenna is a truck-mounted antenna that injects a 2-4 amp, 165kHz signal into the rail.

Apparently, the antenna is so close to the rail it runs afoul of regulations regarding how close locomotive appliances can be to the railhead:

Amtrak seeks relief from 49 CFR 229.71, Clearance above top of rail, to implement the locomotive-mounted shunt enhancer antenna. Section 229.71 states that no part or appliance of a locomotive (excepting “the wheels, flexible nonmetallic sand pipe extension tips, and trip cock arms”) may be within 2.5 inches from the top of rail. Amtrak, which seeks to install the shunt enhancers on its fleet of Siemens Charger SF4 locomotives, explains that under conditions of worn wheels and dynamic profiles, “the mechanical and electrical hardware of the truck-mounted antenna devices could protrude below 2.5 inches from the top of rail.

This Trains article has a photo of the antenna. It hangs down between the wheels, parallel to the rail.

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Re: Shunt enhancement - success?

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It has been stated that Amtrak might be interested in trying to operate their trains from the east and Michigan over the South Shore on the journey into Chicagoland so as to avoid the frequent congestion on the NS Water Level Route. The South Shore Line may not agree with this proposal. But there it is. Perhaps there is a long term vision (among some) that Amtraks from Michigan will connect to the CSS’ newly double tracked mainline in Michigan City using an improved version of the existing freight connection. This hypothetical being the case, getting the PM onto the AML near New Buffalo would allow it to also connect onto the CSS at MCity. The CSS and Grand Rapids Sub do have a connection near the overpass east of Michigan City, but the switch on the CSXT side is currently pulled and the connection track is used for CSS car storage.

As for double tracking Glenwood segment east of Niles, just 1 scheduled meet as Buster noted above. I think a scheduled meet was the pretense for re-double-tracking the segment between CP Mort (Dearborn) and Wayne Jcr. Giving many miles of continuous double track from Townline to Ypsi. This was for the 352-355 meet. But since a schedule change a few years ago, that meet is scheduled for Chelsea, not this eastern segment. Is there another segment of the Michigan Line where more scheduled meets take place where a double track for rolling meets would be more beneficial? I’m using a phone and not really able to consult the RPA printable timetable.

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Re: Shunt enhancement - success?

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GP30M4216 wrote:
Fri May 31, 2024 10:11 pm
It has been stated that Amtrak might be interested in trying to operate their trains from the east and Michigan over the South Shore on the journey into Chicagoland so as to avoid the frequent congestion on the NS Water Level Route. The South Shore Line may not agree with this proposal. But there it is. Perhaps there is a long term vision (among some) that Amtraks from Michigan will connect to the CSS’ newly double tracked mainline in Michigan City using an improved version of the existing freight connection. This hypothetical being the case, getting the PM onto the AML near New Buffalo would allow it to also connect onto the CSS at MCity. The CSS and Grand Rapids Sub do have a connection near the overpass east of Michigan City, but the switch on the CSXT side is currently pulled and the connection track is used for CSS car storage.
This idea was discussed when NICTD got the full funding agreement for DTNWI. However, my guess is now that there are typically too many NICTD trains already to try adding in a bunch of Amtrak express moves, and make it work. Somebody would have to lose when the schedule falls apart, and neither is going to want to budge on that issue.

With 56 scheduled passenger trains west of Miller, and 42 between Miller and Michigan City, almost all between 4a and 7p, the South Shore is a very busy railroad now.
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Re: Shunt enhancement - success?

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Saturnalia wrote:
Sat Jun 01, 2024 7:00 am
This idea was discussed when NICTD got the full funding agreement for DTNWI. However, my guess is now that there are typically too many NICTD trains already to try adding in a bunch of Amtrak express moves, and make it work. Somebody would have to lose when the schedule falls apart, and neither is going to want to budge on that issue.

With 56 scheduled passenger trains west of Miller, and 42 between Miller and Michigan City, almost all between 4a and 7p, the South Shore is a very busy railroad now.
Make that 66 trains west of Hammond when the Monon Connection opens next year.

Mike Noland was asked about Amtrak on NICTD during the Sandhouse presentations in February. He stated that NICTD was involved in the "South of the Lake" discussions and outlined several reasons why following the NICTD path would not be a good idea. (The number of NICTD passenger trains and lack of space to add a third track for Amtrak through the National Park being highlights of the problems.) It is good that NICTD is involved in SOTL. I would not want other participants assuming they could have access to NICTD without including NICTD in the discussion.

NICTDs infrastrcture works well as a commuter line with trains providing service to the cities the line passes through. I don't believe it would work as well for through passenger trains. Amtrak's previous trips to Michigan City from Chicago were scheduled at 63 minutes and 68 minutes (the train that stopped at Hammond). They gave their only westbound 88 minutes to reach Chicago (we call that schedule padding).

Any time "gained" by being on NICTD could be lost by not being on higher speed track from Michigan City to Portage plus the new Chicago connection and Michigan City connections could add time. And while there can be delays on NS, NS has several miles of third main where they can put a train. The schedule for Amtrak would need to be much tighter on NICTD.

Especially on the section of with 66 NICTD passenger trains.

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