What can I say about Day Out With Thomas that has not already been said? The weather Sunday was warm and sunny, and the event seemed to go off without a hitch.
Monday, July 13, 2026
Thomas Day 2
Frank writes…
I signed up to run the 3142; here's our trusty 169-series car ready to leave the yard. But oops - I forgot to bring my run number tag. Fortunately, Zach, who was running the 144, came to the rescue.
The run number tag he procured for me had a familiar name scrawled on the back!
Here's a sharp-looking lineup, and in chronological order, no less. Zach and Randy were on the 144, while Jeff O. and Joseph were on the 4391. Jeff F. was my lunch relief, much appreciated as always. We also had a visit from Jeremy, an old Seashore volunteer now living in California.
After the service cars were back in the barn at the end of the afternoon, the guys did some switching to reload the 'Liner into Barn 7. Here's a sight to warm the heart of any Highwood aficionado.
The 354 was taken on a test trip around the streetcar loop and passed with flying colors, from what I'm told. I don't think I'd mentioned this, but the 354 started experiencing the same "frog striking" problem at South Junction that the 18 did, and at about the same time. Fortunately, the track repair that was put into effect a few weeks ago seems to have done the trick for this car, as well. Depending on volunteer time and inspection schedules, the 354 may again be making occasional appearances in service.
Sounds like the frog striking problem was related to "compromise wheels" which blended railroad profiles with streetcar profiles, and was used on some interurban or suburban lines. TM streetcars had these (and the 354 on TM trucks). I don't know about the 18. O Anderson
ReplyDelete"Compromise Wheels", which typically have a significantly wider tread compared to streetcar wheels (so as to make them compatible with non-flange-bearing track frogs) are only part of the issue.
ReplyDeleteThe most critical issue for compatibility between a wheelset and guarded special trackwork is the "back-to-back" dimension between the wheels on an axle. On a railroad, that dimension is usually set at 53 3/8 inches. With that dimension, wheelsets will track smoothly through the frog, assuming the track gauge, check gauge, and flangeways at a frog and its guard rails are all constructed and maintained within tolerances.
But standard gauge wheelsets that were used in streetcar service on track with flange-bearing frogs typically had a back-to-back dimension of 54 inches, as well as skinnier and shorter flanges. Compromise wheels that have a back-to-back dimension closer to a streetcar standards versus the narrower railroad standard would have a high probability of the type of problems you've reported with Shaker 18 and North Shore 354.
Here at Pennsylvania Trolley Museum, we have somewhat the opposite problem. Nearly all of our frogs are flange bearing and frog check gauge standards are set for compatibility with our (broad gauge) Pittsburgh and Philadelphia city system streetcars. Red Arrow equipment, even though broad gauge, requires special attention since their back-to-back dimension standards were appreciably narrower. As Red Arrow trucks receive maintenance attention, we adjust their back-to-back dimension closer to the Pittsburgh standard dimension of 60 1/8 inches. Those of you who attended the NEATO Winterfest event at PTM back in March may have seen in our Reliance Shop a wheelset being machined to a wider back-to-back.
The great thing about standards is that there are so many of them!
/s/ Larry
Pennsylvania Trolley Museum, Inc.
Larry, thanks for your comments! That's exactly right. We're mostly using two types of compromise wheels at IRM, Shaker wheels and Milwaukee Electric wheels, but they seem pretty similar to each other, at least regarding back-to-back. In this case, the guard rail on the inside of the South Junction switch was pulling the wheels away from the frog, so to speak - but with the greater back-to-back of the compromise wheels, it wasn't not pulling them quite far enough, so they were riding up onto the point of the frog.
ReplyDeleteOf course, the switch in question at South Junction also sees considerable traffic from Chicago Surface Lines cars (like 144, 1374, and 3142) that were re-wheeled with AAR-profile wheels, not to mention plenty of actual railroad equipment - diesels, Pullman cars, etc. Fortunately, this was really an edge case. The back-to-back on both the 18 and 354 is only about 1/8" wider than the back-to-back on the 4391, which navigates the switch okay and uses Shaker compromise wheels like the 18. So, we've been able to make some very minor adjustments that enable the compromise-wheel cars to go through the switch and don't seem to have any adverse effect on the equipment with AAR wheels.
Larry, I was lucky enough to get a detailed description from Arty of all the work he's doing machining wheels for car 73 to get them to PRys profile - extremely impressive stuff! I got a photo of him demonstrating a custom-machined wheel profile gauge that I included in my Winterfest post this past March.