Antenna answer

Either of the two antennas seem to be overpriced for what they are. If there is a two-way radio shop in your area ask for a VHF baseloaded antenna with a magnet mount base with a BNC connector on it. The antenna comes with instructions for cutting the whip to the proper length for 160-162 MHz. 

Looking online for a 144 MHz (2 meter) amateur radio will also provide many options, likely for less. Since all you are doing is listening, the length of the antenna rod isn't super critical. But if you want to fine tune it for the rail band, the rod can be cut.  

Anything is better than the rubber antenna mounted directly to the scanner and getting it outside the vehicle also helps.

Antenna answer

Something like this would work for you. https://www.ebay.com/itm/351731773997?epid=691375552&hash=item51e4d8f22d:g:KwkAAOSwxehXPIlt

My recommendation also. I

Thank you for your comments! 

Thank you for your comments!   My scanner is a Bearcat BC100 XLT that is good Lord about 20 plus years old but works fine.   I bought this from the long out of business Amateur Electronics out of Milwaukee Wisconsin.  The antenna is a Motorola one for the RR freqs., purchased through a local radio shop that services emergency vehicles, and my local municipalities various departments.   Maybe I'll stop by and talk to them for their input as well.   I do agree, both RailCom and Traintenna are overpriced, although Traintenna is $79.00, versus the other at $100 plus...........    At this time, I'm not in a rush, just looking to see what my options are.

My recommendation

https://www.ebay.com/itm/131294324669?hash=item1e91c067bd:g:gbwAAOSwdjdaFd

Generally VHF mobile antennas

Generally VHF mobile antennas fall into one of 2 categories , 1/4 wave or 5/8 wave. the 1/4 wave is more compact , less likely to run into issues with clearance . The 5/8 is longer and has superior gain at low angles (greater range) . 

1/4 wave

https://www.hamradio.com/detail.cfm?pid=H0-003465

5/8 wave

https://www.hamradio.com/detail.cfm?pid=H0-014319

Any ham store just about will have them  . The 5/8 is by far the most popular.

The best place to mount is in the center of the roof , you get the best most efficient pattern .

Thank you for your comments. 

Thank you for your comments.   I am likewise also doing some thinking about how I care to proceed.

Real men drill holes for the antennas too!

A 3/8" or 3/4" permanent NMO mount as high up as possible is the preferable way to go. It doesn't affect the resale value very much. The magnets scratch the paint more than you think if you keep taking it off and the cable can cause leaks when it rains if you aren't careful.

If your going to drill a hole

If your going to drill a hole , You mount the antenna to the toolbox or sub plate  on the truck and then you don't have to worry about leaks or devaluing the vehicle on trade in.