This is an odd one. Purchased as a gamble/curiosity just to see more. Could be fabricated, although I'm not sure to what end. The price I paid wasn't substantially more than what the bond would otherwise bring.
It's an attractive $1,000 railroad bond with a 50-cent battleship documentary affixed, with a 2-line 1899 handstamp cancel. It also has an orange British 1-pound embossed revenue stamp at left, also (I believe) dated 1899.
The odd aspect is the block of 6 1-cent Franklin postage stamps at bottom left, with pen manuscript cancel.
Some things I discovered:
1. Per Wikipedia, the Colorado Midland Railway ceased operations in 1918, well before the postage stamps were issued.
2. The block of 6 is strategically placed on top of a large-format violet handstamp which appears to be related to a court case or dissolution of the company. I've included an image of the handstamp from another example of the bond I found online. All examples of this bond I've been able to find online have this same handstamp, and all bonds are uncancelled.
3. The manuscript cancel on the postage stamp block, per Retroreveal, is "Oct 4 1927" which aligns with the presence/absence of the attached biannual bond coupons. Coupons prior to 1928 are not present, but coupons from January 1928 through July 1947 are still affixed.
So... what is going on here? Would interest still have been paid on the bond following dissolution of the company in 1918? What happened in 1927 to precipitate the affixing and dating of the stamps... part of an estate perhaps?
Images and links to high-resolution versions follow.
Link to High-res version: https://revenue-collector.com/color...midland1.jpg
Link to High-res version: https://revenue-collector.com/color...midland2.jpg
Link to High-res version: https://revenue-collector.com/color...midland3.jpg
Link to High-res version: https://revenue-collector.com/color...midland4.jpg
Closeup of UK embossed revenue:
Closeup of 50-cent battleship documentary:
Closeup of postage stamp block overlaying violet handstamp:
Manuscript cancel per Retroreveal:
Other examples of this bond found online and the handstamp: